Investigation into the Sleep-Promoting Effects of the Traditional Use of Passionflower (Passiflora spp.), Chamomile (Matricaria chamomilla L.) and Mulungu (Erythrina spp.) in Brazil

Abstract

Background/Objectives: Sleep is essential to human health, playing a vital role in physical and mental well-being. Sleep disorders can lead to significant health complications, such as cardiovascular problems, diabetes, obesity, and depression. In Brazil, plants such as passionflower (Passiflora spp.), chamomile (Matricaria chamomilla L.) and mulungu (Erythrina spp.) are widely used in folk medicine for their sleep-promoting properties. This article reviews the existing literature on the sleep-promoting effects of these plants, focusing on the Brazilian context and popular knowledge of their use. Methods: An integrative literature review was conducted, including scientific articles in English and Portuguese from PubMed, Scielo and Google Scholar databases. Ethnobotanical studies documenting the traditional use of these plants in Brazil and clinical and preclinical research on their sleep-promoting effects were included. Results: The juice and infusion of the leaves and fruits of passionflower are mainly used to treat anxiety and insomnia, chamomile flower tea is used for its sedative effects, and mulungu bark decoctions are used for their sedative and anxiolytic properties. These popular uses are supported by scientific studies demonstrating the efficacy of these plants in treating insomnia, anxiety, and stress. Conclusions: The recognition of traditional knowledge and the inclusion of these plants in RENISUS highlights their importance for public health in Brazil. However, more rigorous clinical trials are needed to confirm their efficacy and safety and ensure their safe integration into modern medicine.

1. Introduction

Quality sleep is essential for human health and plays a crucial role in both physical and mental well-being. Insomnia can lead to cognitive issues, including difficulty concentrating, reduced learning ability, and significant mood swings. Sleep issues are common and can negatively impact overall health, increasing the risk of cardiovascular disease, diabetes, obesity, and depression [1]. During sleep, the brain undergoes a ’cleansing’ process. Metabolic waste accumulated during wakefulness is cleared, promoting neural health and overall well-being [2]. Sleep also promotes memory consolidation. This process allows new information to be integrated into long-term memory [3].

Medicinal plants have been used by different cultures throughout history to treat various ailments, including sleep disorders [4]. In Brazil, passionflower (Passiflora spp.), chamomile (Matricaria chamomilla L.), and mulungu (Erythrina spp.) are widely recognised for their medicinal properties. Among their many health benefits, their calming, anxiolytic, and anti-inflammatory properties stand out, along with their ability to promote sleep and alleviate insomnia. In addition, these plants have great cultural and historical significance in Brazil and have been traditionally used in folk medicine [5,6,7,8,9,10].

Passiflora spp., Matricaria chamomilla L., and Erythrina mulungu Mart. are listed in RENISUS (the National List of Medicinal Plants of Interest to the SUS) due to their potential to generate products relevant to the Brazilian Unified Health System (SUS). Their inclusion underscores their significance for public health and reinforces the need for the safe and effective use of traditional medicinal plants in integrative and complementary health practices [11].

Passiflora spp. (Passifloraceae), commonly known as passionflower or passion fruit, is native to tropical and subtropical regions of the Americas [12]. Passionflower has a long history of use in traditional Brazilian medicine and is valued for its calming and sedative properties. Ethnobotanical studies show that the leaves and flowers of this plant are often used to prepare teas and extracts for the treatment of insomnia, anxiety, and other nervous disorders [13]. Research by Dhawan and colleagues [14] highlights flavonoids as the main bioactive compounds responsible for these effects, in addition to their proven antioxidant and anti-inflammatory properties [15].

Matricaria chamomilla L. (Asteraceae) is widely used in traditional medicine around the world, including in Brazil. Chamomile is known for its anti-inflammatory, antispasmodic, and calming properties [16]. Ethnobotanical studies suggest its use in the relief of gastrointestinal symptoms such as colic and indigestion, and in the treatment of anxiety and insomnia [17]. Sah and colleagues [18] identified the presence of apigenin and other flavonoids as key compounds responsible for the therapeutic effects of chamomile.

Erythrina mulungu Mart. (Fabaceae) is a native Brazilian tree traditionally used for its anxiolytic and sedative properties [19]. Rambo and colleagues [20] identified Erythrina-type alkaloids that contribute to the pharmacological properties of the plant.

This study aimed to review the literature on the sleep-promoting effects of passionflower, chamomile, and mulungu, with a focus on studies conducted in Brazil and an emphasis on traditional knowledge of their use. In addition, this work aims to valorise the richness of Brazilian traditional knowledge and ancestral practices in health care and well-being.

2. Results

The literature search yielded 124 relevant articles. After the initial selection and exclusion of ineligible studies, 29 articles were included in the review, all classified as ethnobotanical studies. These articles provided a comprehensive overview of the sleep-promoting effects of the plants studied. The results for each species are presented in the following tables: Table 1 summarises studies on passionflower, Table 2 on chamomile, and Table 3 on mulungu.

Table 1. Sleep-inducing properties of passionflower (Passiflora spp.) according to traditional use in Brazil.

Species	Popular Name in Brazil	Effect	Plant Part	Preparation Method	Study Area *	Reference
Passiflora coccinea Aubl.	Maracujá	Sedative	Leaves, fruit pulp	Infusion, water maceration, juice	Eldorado, Jacupiranga and Sete Barras (SP)	[21]
Passiflora alata Curtis Passiflora edulis Sims	Maracujá, maracujá-do-mato, maracujá-de-casa, maracujina	Soothing, “for nerves”, “tranquilliser”	Leaves, fruits	Jam, fruit, juice	Porto Alegre (RS)	[22]
Passiflora edulis Sims	Maracujá	Sedative	Fruit pulp	Juice	Northeast	[23]
Passiflora sp. Passiflora caerulea L.	Maracujá	Treats nervousness, anxiety and insomnia; sedation	Nm **	Nm	Pelotas, Morro Redondo, Canguçu, Turuçu, Arroio do Padre (RS)	[24]
Passiflora edulis Sims Passiflora cincinnata Mast.	Maracujá, maracujá-do-mato	Soothing	Leaves	Decoction	Aiuaba (CE)	[25]
Passiflora edulis	Maracujá	Soothing	Nm	Nm	Durandé (MG)	[26]
Passiflora incarnata L.	Maracujá	Soothing, anti-fatigue	Fruits	Juice	Queimadas (PB)	[27]
Passiflora edulis Passiflora sp.	Maracujá, maracujá-açu	Soothing	Leaves, fruits	Tea, “lambedor”	Camocim de São Félix (PE)	[28]
Passiflora edulis Sims	Maracujá	Soothing	Fruit peel	Powder	Picuí (PB)	[29]
Passiflora edulis Sims	Maracujá	Sleep aid; treats distress and anxiety	Fruit peel, leaves, flower	Nm	Porteirinha (MG)	[30]
Passiflora edulis Sims	Maracujá	Soothing	Leaves	Infusion	São Gabriel (RS)	[31]
Passiflora alata Curtis	Maracujá	Soothing	Nm	Nm	Vale do Juruena region (MT)	[32]
Passiflora sp.	Maracujá do mato	Soothing; resolves nervousness	Leaves, fruits, roots	Infusion	Exu (PE)	[33]
Passiflora edulis Sims	Maracujá	Soothing	Nm	Powder, juice	Cuité (PB)	[34]
Passiflora sp.	Maracujá do mato	Soothing	Leaves	Decoction, juice	Antonina do Norte (CE)	[35]
Passiflora edulis	Maracujá	Resolves nervousness	Leaves	Infusion, decoction	Vitória da Conquista (BA)	[36]
Passiflora edulis Sims	Maracujá	Treats anxiety and insomnia	Flower, leaves	Juice, infusion	Cuitegi (PB)	[37]
Passiflora edulis Sims.	Maracujá	“To relieve nervousness”	Fruits, leaves	Juice, infusion	Northeast region (17 cities)	[38]
Passiflora edulis Sims.	Maracujá	Soothing, treats insomnia	Leaves, fruits	Decoction, juice	Maceió (AL)	[39]
Passiflora cincinnata	Maracujá do mato	Stress relief, treats anxiety and insomnia	Leaves	Nm	Juazeiro do Norte (CE)	[40]
Passiflora edulis Sims	Maracujá	Soothing to sleep	Leaves	Tea	São João das Missões (MG)	[41]

* Abbreviations in brackets refer to Brazilian states: SP—São Paulo; RS—Rio Grande do Sul; CE—Ceará; MG—Minas Gerais; PB—Paraíba; PE—Pernambuco; MT—Mato Grosso; BA—Bahia; AL—Alagoas. ** Nm = not mentioned in the original article.

Table 1. Sleep-inducing properties of passionflower (Passiflora spp.) according to traditional use in Brazil.

Species	Popular Name in Brazil	Effect	Plant Part	Preparation Method	Study Area *	Reference
Passiflora coccinea Aubl.	Maracujá	Sedative	Leaves, fruit pulp	Infusion, water maceration, juice	Eldorado, Jacupiranga and Sete Barras (SP)	[21]
Passiflora alata Curtis Passiflora edulis Sims	Maracujá, maracujá-do-mato, maracujá-de-casa, maracujina	Soothing, “for nerves”, “tranquilliser”	Leaves, fruits	Jam, fruit, juice	Porto Alegre (RS)	[22]
Passiflora edulis Sims	Maracujá	Sedative	Fruit pulp	Juice	Northeast	[23]
Passiflora sp. Passiflora caerulea L.	Maracujá	Treats nervousness, anxiety and insomnia; sedation	Nm **	Nm	Pelotas, Morro Redondo, Canguçu, Turuçu, Arroio do Padre (RS)	[24]
Passiflora edulis Sims Passiflora cincinnata Mast.	Maracujá, maracujá-do-mato	Soothing	Leaves	Decoction	Aiuaba (CE)	[25]
Passiflora edulis	Maracujá	Soothing	Nm	Nm	Durandé (MG)	[26]
Passiflora incarnata L.	Maracujá	Soothing, anti-fatigue	Fruits	Juice	Queimadas (PB)	[27]
Passiflora edulis Passiflora sp.	Maracujá, maracujá-açu	Soothing	Leaves, fruits	Tea, “lambedor”	Camocim de São Félix (PE)	[28]
Passiflora edulis Sims	Maracujá	Soothing	Fruit peel	Powder	Picuí (PB)	[29]
Passiflora edulis Sims	Maracujá	Sleep aid; treats distress and anxiety	Fruit peel, leaves, flower	Nm	Porteirinha (MG)	[30]
Passiflora edulis Sims	Maracujá	Soothing	Leaves	Infusion	São Gabriel (RS)	[31]
Passiflora alata Curtis	Maracujá	Soothing	Nm	Nm	Vale do Juruena region (MT)	[32]
Passiflora sp.	Maracujá do mato	Soothing; resolves nervousness	Leaves, fruits, roots	Infusion	Exu (PE)	[33]
Passiflora edulis Sims	Maracujá	Soothing	Nm	Powder, juice	Cuité (PB)	[34]
Passiflora sp.	Maracujá do mato	Soothing	Leaves	Decoction, juice	Antonina do Norte (CE)	[35]
Passiflora edulis	Maracujá	Resolves nervousness	Leaves	Infusion, decoction	Vitória da Conquista (BA)	[36]
Passiflora edulis Sims	Maracujá	Treats anxiety and insomnia	Flower, leaves	Juice, infusion	Cuitegi (PB)	[37]
Passiflora edulis Sims.	Maracujá	“To relieve nervousness”	Fruits, leaves	Juice, infusion	Northeast region (17 cities)	[38]
Passiflora edulis Sims.	Maracujá	Soothing, treats insomnia	Leaves, fruits	Decoction, juice	Maceió (AL)	[39]
Passiflora cincinnata	Maracujá do mato	Stress relief, treats anxiety and insomnia	Leaves	Nm	Juazeiro do Norte (CE)	[40]
Passiflora edulis Sims	Maracujá	Soothing to sleep	Leaves	Tea	São João das Missões (MG)	[41]

* Abbreviations in brackets refer to Brazilian states: SP—São Paulo; RS—Rio Grande do Sul; CE—Ceará; MG—Minas Gerais; PB—Paraíba; PE—Pernambuco; MT—Mato Grosso; BA—Bahia; AL—Alagoas. ** Nm = not mentioned in the original article.

Table 2. Sleep-inducing properties of chamomile according to traditional use in Brazil (Matricaria chamomilla L. is the accepted species name in World Flora Online).

Species	Popular Name in Brazil	Effect	Plant Part	Preparation Method	Study Area *	Reference
Matricaria recutita	Camomila	Sedative; sedative for children	Leaves, seeds	Internal use	Eldorado, Jacupiranga and Sete Barras (SP)	[21]
Matricaria chamomilla	Camomila	Soothing	Nm **	Nm	Marília (SP)	[42]
Matricaria chamomilla L.	Camomila	Resolves nervousness	Flowers	Cooking	Juazeiro (BA)	[43]
Chamomilla recutita (L.)	Camomila	Soothing	Leaves, seeds	Decoction	Aiuaba (CE)	[25]
Matricaria chamomilla L.	Camomila	Soothing	Nm	Nm	Durandé (MG)	[26]
Chamomilla recutita L.	Camomila	Soothing	Flowers	Infusion	Queimadas (PB)	[27]
Chamomilla recutita	Camomila	Soothing	Leaves, flowers	Tea	Camocim de São Félix (PE)	[28]
Chamomilla recutita (L.) Rauschert	Camomila	Soothing, stress relief	Flowers	Tea, bath	Picuí (PB)	[29]
Chamomilla recutita (L.) Rauschert	Camomila	Resolves nervousness	Flowers	Tea	Nova Palmeira, Frei Martinho (PB)	[29]
Chamomilla recutita (L.) Rauschert	Camomila	Tranquiliser, sleep aid	Leaves, flowers	Nm	Porteirinha (MG)	[30]
Chamomilla recutita (L.) Rauschert	Camomila	Soothing	Flowers	Tea	Puxinanã (PB)	[44]
Matricaria chamomilla L.	Camomila	Soothing	Flowers	Infusion	São Gabriel (RS)	[31]
Matricaria chamomilla L.	Camomila	Soothing	Nm	Nm	Vale do Juruena region (MT)	[32]
Matricaria chamomilla L.	Camomila	Soothing, treats insomnia	Nm	Infusion	Cuité (PB)	[34]
Matricaria chamomila L.	Camomila	Resolves nervousness, soothing, treats insomnia	Flowers, seeds, leaves	Infusion	Antonina do Norte (CE)	[35]
Matricaria chamomilla L.	Camomila	Tranquiliser	Flowers	Infusion	Vitória da Conquista (BA)	[36]
Chamomilla recutita (L.) Rauschert	Camomila	Anti-anxiety	Flowers	Decoction	Cuitegi (PB)	[37]
Chamomilla recutita L.	Camomila	Soothing	Flowers	Tea	Barra de Santa Rosa, Cuité, Nova Floresta, Baraúna, Picuí e Jaçanã (RN)	[45]
Matricaria recutita L.	Camomila	Soothing	Flowers	Infusion, decoction	Maceió (AL)	[39]
Matricaria chamomilla (L.) Rauschert	Camomila	Resolves nervousness; tranquiliser	Flowers	Decoction, infusion	Araçagi (PB)	[46]
Matricaria chamomilla L.	Camomila	Treats insomnia, stress and anxiety; soothing	Flowers	Infusion	Juazeiro do Norte (CE)	[40]
Matricaria chamomilla L.	Camomila	Soothing	Flowers	Nm	Brejo da Madre de Deus (PE)	[47]

* Abbreviations in brackets refer to Brazilian states: SP—São Paulo; BA—Bahia; CE—Ceará; MG—Minas Gerais; PB—Paraíba; RS—Rio Grande do Sul; MT—Mato Grosso; RN—Rio Grande do Norte; AL—Alagoas; PE—Pernambuco. ** Nm = not mentioned in the original article.

Table 2. Sleep-inducing properties of chamomile according to traditional use in Brazil (Matricaria chamomilla L. is the accepted species name in World Flora Online).

Species	Popular Name in Brazil	Effect	Plant Part	Preparation Method	Study Area *	Reference
Matricaria recutita	Camomila	Sedative; sedative for children	Leaves, seeds	Internal use	Eldorado, Jacupiranga and Sete Barras (SP)	[21]
Matricaria chamomilla	Camomila	Soothing	Nm **	Nm	Marília (SP)	[42]
Matricaria chamomilla L.	Camomila	Resolves nervousness	Flowers	Cooking	Juazeiro (BA)	[43]
Chamomilla recutita (L.)	Camomila	Soothing	Leaves, seeds	Decoction	Aiuaba (CE)	[25]
Matricaria chamomilla L.	Camomila	Soothing	Nm	Nm	Durandé (MG)	[26]
Chamomilla recutita L.	Camomila	Soothing	Flowers	Infusion	Queimadas (PB)	[27]
Chamomilla recutita	Camomila	Soothing	Leaves, flowers	Tea	Camocim de São Félix (PE)	[28]
Chamomilla recutita (L.) Rauschert	Camomila	Soothing, stress relief	Flowers	Tea, bath	Picuí (PB)	[29]
Chamomilla recutita (L.) Rauschert	Camomila	Resolves nervousness	Flowers	Tea	Nova Palmeira, Frei Martinho (PB)	[29]
Chamomilla recutita (L.) Rauschert	Camomila	Tranquiliser, sleep aid	Leaves, flowers	Nm	Porteirinha (MG)	[30]
Chamomilla recutita (L.) Rauschert	Camomila	Soothing	Flowers	Tea	Puxinanã (PB)	[44]
Matricaria chamomilla L.	Camomila	Soothing	Flowers	Infusion	São Gabriel (RS)	[31]
Matricaria chamomilla L.	Camomila	Soothing	Nm	Nm	Vale do Juruena region (MT)	[32]
Matricaria chamomilla L.	Camomila	Soothing, treats insomnia	Nm	Infusion	Cuité (PB)	[34]
Matricaria chamomila L.	Camomila	Resolves nervousness, soothing, treats insomnia	Flowers, seeds, leaves	Infusion	Antonina do Norte (CE)	[35]
Matricaria chamomilla L.	Camomila	Tranquiliser	Flowers	Infusion	Vitória da Conquista (BA)	[36]
Chamomilla recutita (L.) Rauschert	Camomila	Anti-anxiety	Flowers	Decoction	Cuitegi (PB)	[37]
Chamomilla recutita L.	Camomila	Soothing	Flowers	Tea	Barra de Santa Rosa, Cuité, Nova Floresta, Baraúna, Picuí e Jaçanã (RN)	[45]
Matricaria recutita L.	Camomila	Soothing	Flowers	Infusion, decoction	Maceió (AL)	[39]
Matricaria chamomilla (L.) Rauschert	Camomila	Resolves nervousness; tranquiliser	Flowers	Decoction, infusion	Araçagi (PB)	[46]
Matricaria chamomilla L.	Camomila	Treats insomnia, stress and anxiety; soothing	Flowers	Infusion	Juazeiro do Norte (CE)	[40]
Matricaria chamomilla L.	Camomila	Soothing	Flowers	Nm	Brejo da Madre de Deus (PE)	[47]

* Abbreviations in brackets refer to Brazilian states: SP—São Paulo; BA—Bahia; CE—Ceará; MG—Minas Gerais; PB—Paraíba; RS—Rio Grande do Sul; MT—Mato Grosso; RN—Rio Grande do Norte; AL—Alagoas; PE—Pernambuco. ** Nm = not mentioned in the original article.

Table 3. Sleep-inducing properties of mulungu (Erythrina spp.) according to traditional use in Brazil.

Species	Popular Name in Brazil	Effect	Plant Part	Preparation Method	Study Area *	Reference
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Infusion or decoction of a handful in one litre of water	Northeast	[23]
Erythrina mulungu Mart. Erythrina velutina Willd.	Mulungu	Calming, treats insomnia and anxiety	Bark, flower, leaf, fruit, seeds	Nm **	Northeast	[48]
Erythrina mulungu Mart. Ex. Benth	Mulungu	Treats nervousness and insomnia	Leaves, bark	Boiling, infusion, steeping	Petrolina (PE), Juazeiro and Sento-Sé (BA)	[43]
Erythrina speciosa	Mulungu	Treats nervousness, anguish, insomnia	Nm	Nm	Pelotas, Morro Redondo, Canguçu, Turuçu and Arroio do Padre (RS)	[24]
Erythrina speciosa Andrews	Pau-cebola, pau-sabão, mulungu	Calming	Nm	Nm	Durandé (MG)	[26]
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Maceration	Queimadas (PB)	[27]
Erythrina mulungu	Mulungu	Calming	Leaf and bark	Tea	Camocim de São Félix (PE)	[28]
Erythrina velutina Willd.	Mulungu	Treats stress and insomnia	Bark	Tea, tincture, traditional herbal syrup preparation (“lambedor”)	Nova Palmeira (PB)	[29]
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Tea	Frei Martinho, PB	[29]
Erythrina mulungu Mart. ex Benth.	Mulungu	Sedative; treats depression	Leaf, inner bark, seed	Nm	Porteirinha (MG)	[30]
Erythrina velutina Willd	Mulungu	Calming	Bark and seed	Tea from the bark, bark soaked in water, crushed seed	Puxinanã (PB)	[44]
Erythrina verna Vell.	Corticeira, mulungu	Treats nervous system problems	Bark	Decoction and tincture	São Pedro do Iguaçu (PR)	[49]
Erythrina verna Vell.	Mulungu	Tranquilizer, resolves nervous crisis, treats depression, stress, and insomnia	Bark and leaves	Infusion, maceration	Norte Araguaia microregion (MT)	[50]
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Decoction	Cuitegi (PB)	[37]
Erythrina velutina Willd.	Mulungu	Treats sleep disorders	Bark (outer and inner), seeds	Infusion, decoction, fresh or powdered	Northeast region (17 cities)	[38]
Erythrina velutina Willd.	Mulungu	Treats nervousness, antidepressant	Bark	Traditional herbal preparations (“garrafadas”)	Barra de Santa Rosa, Cuité, Nova Floresta, Baraúna, Picuí and Jaçanã (RN)	[45]
Erythrina velutina Vell.	Mulungu	Treats insomnia, anxiety, and depression	Bark	Infusion	Juazeiro do Norte (CE)	[40]
Erythrina velutina Willd.	Mulungu	Calming	Bark	Nm	Brejo da Madre de Deus (PE)	[47]
Erythrina verna Vell.	Casca-de-mulungu	Treats insomnia	Bark	Tea	São João das Missões (MG)	[41]

* Abbreviations in brackets refer to Brazilian states: PE—Pernambuco; BA—Bahia; RS—Rio Grande do Sul; MG—Minas Gerais; PB—Paraíba; PR—Paraná; MT—Mato Grosso; RN—Rio Grande do Norte; CE—Ceará. ** Nm = not mentioned in the original article.

Table 3. Sleep-inducing properties of mulungu (Erythrina spp.) according to traditional use in Brazil.

Species	Popular Name in Brazil	Effect	Plant Part	Preparation Method	Study Area *	Reference
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Infusion or decoction of a handful in one litre of water	Northeast	[23]
Erythrina mulungu Mart. Erythrina velutina Willd.	Mulungu	Calming, treats insomnia and anxiety	Bark, flower, leaf, fruit, seeds	Nm **	Northeast	[48]
Erythrina mulungu Mart. Ex. Benth	Mulungu	Treats nervousness and insomnia	Leaves, bark	Boiling, infusion, steeping	Petrolina (PE), Juazeiro and Sento-Sé (BA)	[43]
Erythrina speciosa	Mulungu	Treats nervousness, anguish, insomnia	Nm	Nm	Pelotas, Morro Redondo, Canguçu, Turuçu and Arroio do Padre (RS)	[24]
Erythrina speciosa Andrews	Pau-cebola, pau-sabão, mulungu	Calming	Nm	Nm	Durandé (MG)	[26]
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Maceration	Queimadas (PB)	[27]
Erythrina mulungu	Mulungu	Calming	Leaf and bark	Tea	Camocim de São Félix (PE)	[28]
Erythrina velutina Willd.	Mulungu	Treats stress and insomnia	Bark	Tea, tincture, traditional herbal syrup preparation (“lambedor”)	Nova Palmeira (PB)	[29]
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Tea	Frei Martinho, PB	[29]
Erythrina mulungu Mart. ex Benth.	Mulungu	Sedative; treats depression	Leaf, inner bark, seed	Nm	Porteirinha (MG)	[30]
Erythrina velutina Willd	Mulungu	Calming	Bark and seed	Tea from the bark, bark soaked in water, crushed seed	Puxinanã (PB)	[44]
Erythrina verna Vell.	Corticeira, mulungu	Treats nervous system problems	Bark	Decoction and tincture	São Pedro do Iguaçu (PR)	[49]
Erythrina verna Vell.	Mulungu	Tranquilizer, resolves nervous crisis, treats depression, stress, and insomnia	Bark and leaves	Infusion, maceration	Norte Araguaia microregion (MT)	[50]
Erythrina velutina Willd.	Mulungu	Treats insomnia	Bark	Decoction	Cuitegi (PB)	[37]
Erythrina velutina Willd.	Mulungu	Treats sleep disorders	Bark (outer and inner), seeds	Infusion, decoction, fresh or powdered	Northeast region (17 cities)	[38]
Erythrina velutina Willd.	Mulungu	Treats nervousness, antidepressant	Bark	Traditional herbal preparations (“garrafadas”)	Barra de Santa Rosa, Cuité, Nova Floresta, Baraúna, Picuí and Jaçanã (RN)	[45]
Erythrina velutina Vell.	Mulungu	Treats insomnia, anxiety, and depression	Bark	Infusion	Juazeiro do Norte (CE)	[40]
Erythrina velutina Willd.	Mulungu	Calming	Bark	Nm	Brejo da Madre de Deus (PE)	[47]
Erythrina verna Vell.	Casca-de-mulungu	Treats insomnia	Bark	Tea	São João das Missões (MG)	[41]

* Abbreviations in brackets refer to Brazilian states: PE—Pernambuco; BA—Bahia; RS—Rio Grande do Sul; MG—Minas Gerais; PB—Paraíba; PR—Paraná; MT—Mato Grosso; RN—Rio Grande do Norte; CE—Ceará. ** Nm = not mentioned in the original article.

3. Discussion

The practice of using medicinal plants is deeply rooted in the cultures and traditions of different regions of Brazil [51]. The diversity of Brazilian flora, exemplified in this study by passionflower, chamomile, and mulungu, contributes to the health and well-being of the population.

The reviewed ethnobotanical studies demonstrated a wide range of sleep-promoting effects associated with the traditional use of Passiflora spp., Matricaria chamomilla, and Erythrina spp. in Brazil. The most reported benefits include treating insomnia, reducing anxiety, and relieving stress. In addition, these plants are often described as calming and sedative, contributing to relaxation and improved sleep quality. Other relevant effects include the treatment of nervous system disorders, as well as their role as tranquilisers and sleep aids. Some studies also highlight the calming effects of these plants, particularly in children. All these effects are related to good sleep health [1] and have been classified in this article as ’sleep-promoting effects’.

Although Passiflora spp. and Erythrina spp. comprise multiple species with different scientific names, the results show species that are popularly known in Brazil as passionflower (maracujá) and mulungu, respectively. This diversity in nomenclature justifies the inclusion of various species in the analysis, such as Passiflora edulis Sims, Passiflora coccinea Aubl., Passiflora alata Curtis, Passiflora caerulea L., Passiflora cincinnata Mast., Passiflora incarnata L., Erythrina velutina Willd., Erythrina mulungu Mart. ex Benth., Erythrina speciosa Andrews, and Erythrina verna Vell. Ethnobotanical studies reviewed here indicate that all these species have sleep-promotion properties. In contrast, despite historical variations in its nomenclature and other botanical names considered synonyms, Matricaria chamomilla remains the only chamomile species taken into account [52].

To discuss the effects of these plants on human health, the therapeutic effects reported by the scientific literature were analysed. The findings were then compared with the results of the ethnobotanical studies presented in this review.

Studies suggest that passionflower is used to treat anxiety and insomnia, possibly due to the presence of flavonoids and alkaloids such as vitexin and chrysin, which have anxiolytic and sedative effects [14,53]. Movafegh and colleagues [54] confirmed these effects in a clinical trial in which oral administration of Passiflora incarnata in tablet form (500 mg, Passipy™ IranDarouk) significantly reduced preoperative anxiety in patients compared with placebo. The tablets were administered 90 min before surgery and led to a significant reduction in anxiety levels without inducing sedation. Anxiety scores measured using the Numeric Rating Scale (NRS) were significantly lower in the Passiflora group than in the control group (p < 0.001). Initial scores were 4.6 ± 1.7 in the Passiflora group and 5.1 ± 2 in the control group. After 90 min, anxiety scores decreased to 3.88 in the control group and 0.97 in the Passiflora group [54].

Chamomile is recognised for its calming and anti-inflammatory properties and has been shown to be effective in treating insomnia and anxiety [16,17]. Zick and colleagues [55] tested a standardised dry hydroethanolic extract of Matricaria recutita flowers (270 mg twice daily) and observed a reduction in sleep latency of about 16 min. In addition, it reduced the number of nighttime awakenings by 0.8 in patients with chronic insomnia. Although the results were moderate, they suggest that chamomile may have a beneficial effect on sleep quality [55]. The flavonoid apigenin, found in chamomile, binds to benzodiazepine receptors, specific proteins that modulate the activity of GABA (gamma-aminobutyric acid), the brain’s primary inhibitory neurotransmitter. This interaction produces sedative and anxiolytic effects, as indicated by Sepp and colleagues [56].

In addition, significant concentrations of luteolin and its glycosylated derivatives were identified and quantified in the hydroethanolic extract of Matricaria chamomilla flowers using UPLC-MS/MS [55]. Luteolin has well-documented anti-inflammatory, antioxidant, and neuroprotective properties. These properties may contribute to the sedative and analgesic effects of chamomile [16,18,56].

Recent clinical trials have investigated the effectiveness of chamomile extract in improving sleep quality and reducing anxiety symptoms. A randomised, controlled trial by Adib-Hajbaghery and Mousavi [57] evaluated the effects of a spray-dried hydroethanolic Matricaria recutita extract on sleep quality in older adults. The treatment group received 200 mg of chamomile extract twice daily for 28 days, while the control group received a placebo. Both groups had poor sleep quality at baseline, as measured by the Pittsburgh Sleep Quality Index (PSQI), but the differences were not significant. However, after the intervention, the treated group improved their sleep quality compared to the placebo group (p < 0.05). This supports the potential of chamomile as a natural sleep aid [57].

In addition, a long-term randomised clinical trial by Mao and colleagues [58] investigated the effects of chamomile extract on generalised anxiety disorder (GAD). In this 38-week, double-blind, placebo-controlled study, participants initially received 1500 mg of pharmaceutical-grade chamomile extract daily for 12 weeks. The hydroethanolic extract of Matricaria chamomilla L. flowers has been standardised to provide 6 mg of apigenin-7-glucosides (Api-7Glc) per 500 mg capsule. Those who had a positive response were then randomised to either continue with chamomile therapy for a further 26 weeks or to switch to a placebo. The chamomile group maintained significantly lower levels of GAD symptoms than the placebo group (p = 0.0032), indicating a sustained anxiolytic effect. Although the time to recurrence of anxiety symptoms was longer in the chamomile group (11.4 ± 8.4 weeks) than in the placebo group (6.3 ± 3.9 weeks), this difference did not reach statistical significance (p = 0.16). Chamomile treatment was well tolerated, with no serious adverse effects reported, and was even associated with a small reduction in blood pressure [58].

These findings support chamomile as a safe and effective alternative for improving sleep quality and reducing anxiety symptoms, particularly in older adults and those with GAD. However, further large-scale clinical trials are needed to confirm the therapeutic potential of chamomile.

Mulungu is traditionally used in Brazil for its sedative and anxiolytic properties [19,38]. Rambo and colleagues [20] have identified alkaloids, such as erysotrine and erythravine, that are thought to be responsible for these effects. Ribeiro and colleagues [59] demonstrated that Erythrina mulungu has anxiolytic potential comparable to diazepam in animal models. A hydroalcoholic extract of mulungu inflorescences was administered orally at acute doses of 100, 200, and 400 mg/kg, and chronic doses of 50, 100, and 200 mg/kg. Mulungu treatment significantly reduced avoidance latencies in the T-maze test, without affecting escape measures, similar to diazepam and without impairing the animals’ motor activity.

Although these findings support the anxiolytic potential of Erythrina spp., clinical trials evaluating its efficacy in humans have been lacking until recently. Recent clinical trials have sought to evaluate the efficacy of Erythrina mulungu in anxiety management in humans. A randomised, placebo-controlled, triple-blind clinical trial by Cunha and colleagues [60] compared the effects of Erythrina mulungu (500 mg, Matusa^® formulation), Passiflora incarnata (500 mg), and midazolam (15 mg) in patients undergoing third molar extraction. Anxiety levels were assessed using questionnaires and physiological parameters such as heart rate, blood pressure, and oxygen saturation. Passiflora incarnata showed anxiolytic effects comparable to midazolam. However, Erythrina mulungu did not differ significantly from the placebo, suggesting that its efficacy may be limited in acute anxiety scenarios, such as preoperative dental anxiety [60].

Erythrina mulungu showed an anxiolytic effect in patients undergoing bilateral third molar extraction in a randomised, double-blind, crossover study by Silveira-Souto and colleagues [61]. A dose of 500 mg of Erythrina mulungu (Matusa^® formulation) was administered one hour before surgery. Patients showed a statistically significant preference for Erythrina mulungu over placebo, particularly among those with higher baseline anxiety levels. No significant differences in physiological parameters (blood pressure, heart rate, and oxygen saturation) were observed between the groups, despite subjective reports of reduced anxiety [61].

These findings highlight the complexity of the anxiolytic potential of Erythrina mulungu. While in vivo studies suggest potent sedative and anxiolytic effects, clinical evidence in humans remains inconclusive. This may be influenced by differences in study design, dosage, and the specific anxiety context being assessed. Further research, particularly large-scale clinical trials, is needed to determine the full therapeutic potential of Erythrina mulungu and its possible applications in modern medicine.

The key bioactive compounds of these medicinal plants, including alkaloids and flavonoids, are listed in Table 4. These compounds are likely to contribute to the anxiolytic and sedative effects reported in both traditional and clinical studies.

Table 4. Key bioactive compounds in Passiflora spp., Matricaria chamomilla, and Erythrina spp. and their biological properties.

Compound	Source Plant	Class	Molecular Structure *	Biological Properties
Vitexin	Passiflora spp.	Flavonoid		Anti-inflammatory [62] Antidiabetic [63] Antitumor [64] Neuroprotective [65]
Chrysin	Passiflora spp.	Flavonoid		Anti-inflammatory [66] Antitumor [67] Hepatoprotective [68] Neuroprotective [69]
Apigenin	Matricaria chamomilla	Flavonoid		Anti-inflammatory [70] Cardioprotective [71] Neuroprotective [72] Anxiolytic [73]
Luteolin	Matricaria chamomilla	Flavonoid		Anti-inflammatory [74] Antihypertensive [75] Anxiolytic [76] Antidepressant [76]
Erysotrine	Erythrina spp.	Alkaloid		Anxiolytic [77] Anticonvulsant [77]
Erythravine	Erythrina spp.	Alkaloid		Anxiolytic [78,79]

* Molecular structures were drawn using ChemDraw^® Ultra 12.0.2 (CambridgeSoft^®).

Table 4. Key bioactive compounds in Passiflora spp., Matricaria chamomilla, and Erythrina spp. and their biological properties.

Compound	Source Plant	Class	Molecular Structure *	Biological Properties
Vitexin	Passiflora spp.	Flavonoid		Anti-inflammatory [62] Antidiabetic [63] Antitumor [64] Neuroprotective [65]
Chrysin	Passiflora spp.	Flavonoid		Anti-inflammatory [66] Antitumor [67] Hepatoprotective [68] Neuroprotective [69]
Apigenin	Matricaria chamomilla	Flavonoid		Anti-inflammatory [70] Cardioprotective [71] Neuroprotective [72] Anxiolytic [73]
Luteolin	Matricaria chamomilla	Flavonoid		Anti-inflammatory [74] Antihypertensive [75] Anxiolytic [76] Antidepressant [76]
Erysotrine	Erythrina spp.	Alkaloid		Anxiolytic [77] Anticonvulsant [77]
Erythravine	Erythrina spp.	Alkaloid		Anxiolytic [78,79]

* Molecular structures were drawn using ChemDraw^® Ultra 12.0.2 (CambridgeSoft^®).

The correlation between the bioactive compounds identified in Passiflora spp., Matricaria chamomilla, and Erythrina spp. and their documented pharmacological properties highlights their therapeutic relevance. Although their anxiolytic and sedative effects have long been recognised in traditional medicine, scientific validation remains inconsistent. Clinical evidence on Passiflora spp. and Matricaria chamomilla is relatively robust, whereas studies on Erythrina spp., particularly Erythrina mulungu, are limited and somewhat contradictory. Preclinical research suggests the anxiolytic potential of Erythrina-type alkaloids. However, the lack of standardised methodologies and the absence of large-scale clinical trials hinder a conclusive understanding of their efficacy [20]. Future research should aim to fill these gaps and ensure that the therapeutic applications of these plants are supported by rigorous scientific evaluation and optimised for clinical use.

In Brazil, Passiflora spp. is widely known for its use in treating anxiety and improving sleep, often consumed as a juice, infusion, or decoction, primarily derived from its leaves and fruits [22,23,31]. Similarly, chamomile (Matricaria chamomilla) is well recognised for its calming effects, and is commonly prepared as an infusion of its flowers [31,40]. Erythrina mulungu, highly valued in traditional medicine, is predominantly used in northeastern Brazil, where its bark is prepared as a decoction for its sedative properties [40,43]. The Brazilian Pharmacopoeia provides official guidelines for the extraction of these plants. According to its monographs, different species of Passiflora are officially recognised for their medicinal properties: Passiflora alata is prepared as an infusion of the leaves in water (1:50 w/v) for its anxiolytic and sedative effects; Passiflora edulis is also used in folk medicine as a sedative; while Passiflora incarnata is used for anxiety and insomnia, typically prepared as an infusion of its aerial parts [80,81]. Matricaria chamomilla is usually consumed as an infusion of its flowers (0.5–4 g per 150 mL of water) for its calming effects [82]. Erythrina mulungu is traditionally used as a decoction of the bark (0.5 g per 150 mL of water) for its sedative properties [82].

These findings highlight the cultural importance of these plants in Brazil. The traditional use of passionflower, chamomile, and mulungu in folk medicine reflects a deep appreciation of the country’s natural resources for promoting human health. Preserving this knowledge is essential to maintaining Brazil’s cultural identity and promoting alternative therapeutic options in medicine. In addition, the inclusion of Passiflora spp., Matricaria chamomilla L., and Erythrina mulungu in RENISUS [11] reinforces the therapeutic potential and cultural significance of these plants in Brazil. These species provide complementary alternatives for the treatment of sleep disorders and anxiety, contributing to overall public health. However, more rigorous clinical trials are required to ensure the safety and efficacy of these treatments in humans. Further research on these plants could contribute significantly to promoting health and well-being in Brazil and globally.

In addition, the wide geographical distribution of the ethnobotanical studies analysed here is highly relevant to this discussion. The fact that studies have been conducted across different regions of Brazil—including the northeast, south, southeast, and midwest—demonstrates the widespread popularity and trust in these medicinal plants among different cultural groups. Figure 1 illustrates the distribution of ethnobotanical studies, highlighting both Brazil’s cultural diversity and rich biodiversity.

The geographical diversity of these plants’ use demonstrates their cultural significance. The alignment between ethnobotanical findings and scientific studies further highlights the importance of recognising and valuing traditional knowledge across diverse cultural and ecological contexts. Each Brazilian region has its own unique practices and adaptations. This diversity enriches the understanding of the use of these plants and highlights traditional wisdom in utilising natural resources for health promotion.

The widespread use of Passiflora spp., Matricaria chamomilla L., and Erythrina spp. for sleep-promoting effects also reinforces the need for public policies that support research and conservation of the biome. Protecting traditional knowledge ensures that its benefits remain widely accessible. This approach not only values Brazilian culture but also contributes to the country’s sustainability and biodiversity.

Herbal medicines containing two of the species studied are already registered with the Brazilian Health Regulatory Agency (ANVISA). According to the ANVISA website [83], there are currently 45 registered herbal medicinal products containing Passiflora incarnata. Of these, 39 contain only Passiflora incarnata, while six are formulated in combination with other plant species, such as Valeriana officinalis, Crataegus rhipidophylla, and Salix alba. All these products are registered under the therapeutic class of anxiolytics, supporting the traditional use reports identified in this study.

In contrast, for Matricaria recutita, only one record was found for an anti-inflammatory ointment (Ad-muc^®, Biolab Sanus Farmacêutica), with no registered herbal medicinal products specifically indicated for sleep promotion. Also, no registered medicines containing mulungu (Erythrina spp.) were found in the ANVISA database. This may indicate a gap in scientific research and validation, or in the regulatory framework for the official medicinal use of this species.

In addition, many of these herbal products registered with ANVISA are classified as PTFs (from the Portuguese Produtos Tradicionais Fitoterápicos, meaning traditional herbal products), as established by a resolution of the Collegiate Council (RDC No. 26/2014) [84]. This type of registration is based on traditional use, where the safety and efficacy of PTFs are based on the demonstration of their safety and effective use for more than thirty years. This type of registration emphasises the importance of traditional knowledge and its recognition within formal medicine. This is also evident in the National Policy on Integrative and Complementary Practices (PNPIC), which promotes the use of traditional treatments, such as phytotherapy, within the Brazilian Unified Health System (SUS) [85].

4. Materials and Methods

This article presents an integrative review of the existing literature to investigate the sleep-promoting effects of the popular use of Passiflora spp., Matricaria chamomilla L. and Erythrina spp. in Brazil. The literature search was carried out in June 2024. The databases used were PubMed, Scielo and Google Scholar. The searches were conducted using specific keyword combinations in Portuguese and English to ensure that the results were relevant and specific. Keywords related to plants, location, context, and effects were defined in the search process. The search included the following keywords: species names ‘Passiflora spp.’, ‘Chamomilla recutita’ and ‘Erythrina mulungu’; Brazil” (English) and “Brasil” (Portuguese) were the keywords related to location; ‘ethnobotanical’ (Portuguese) and ‘ethnobotanical’ (English) were the keywords related to the context; and the keywords related to sleep-promoting effects were ‘ansiolítico’, ‘sedativo’, ‘calmante’, ‘insônia’ (Portuguese) and ‘anxiolytic’, ‘sedative’, ‘calming’, ‘insomnia’ (English).

The inclusion criteria were as follows: scientific articles in English and Portuguese; studies investigating the sleep-promoting effects of Passiflora spp., Matricaria chamomilla L. and Erythrina spp., with emphasis on research conducted in the Brazilian context; and ethnobotanical studies documenting the popular use of these plants in Brazil. Papers written in languages other than English or Portuguese, those that did not correlate a sleep-promoting effect with the popular use of these plants in the Brazilian context, and those that were not ethnobotanical in nature, i.e., that did not document the traditional or popular use of the plants, were not included in this study.

During the data extraction process, key information from the selected articles was recorded. This included the plant species mentioned in each study, the popular name reported in Portuguese by interviewees in ethnobotanical studies, the sleep-promoting effects associated with traditional use, the plant parts used, the preparation method, and the study location.

The information was tabulated to facilitate interpretation, and the results were discussed considering the reviewed literature. This approach highlights their contributions to understanding the sleep-promoting effects of these plants in the context of traditional Brazilian medicine.

5. Conclusions

This study demonstrated that Passiflora spp., Matricaria chamomilla L., and Erythrina spp. play significant roles in Brazilian folk medicine and are widely used for their sleep-promoting properties. Both clinical and preclinical trials validate the effects observed in traditional practice, particularly in the treatment of anxiety and sleep disorders.

Preservation and ongoing research into these medicinal plants are essential, not only because of Brazil’s rich biodiversity but also due to their cultural value and therapeutic potential. The inclusion of these plants in RENISUS highlights their importance and the need for further research to confirm their efficacy and safety, ensuring their safe integration into modern medicine.

Future research should focus on robust clinical trials to validate their traditional uses and explore new therapeutic applications, as well as further examine the cultural significance of these plants in various regions of Brazil. The combination of traditional knowledge with modern science can provide effective and innovative solutions to global health challenges, benefiting both Brazilian and global populations.