**1. Introduction**

The placenta joins the fetus to the mother and functions as a means of transport to transfer nutrients such as glucose, amino acids, fatty acids, vitamins, and other minerals essential for fetus growth and development [1]. The nutrients supplied by the placenta may be retained after the birth of the fetus [2,3]. Collagen, elastin, laminin, vitamins, trace minerals, nucleic acids, amino acids, peptides, cytokines, and growth factors have all been identified in human placental extracts [4–7].

With its high nutritional content and biologically active components, the placenta has historically been valued as a traditional folk medicine in China and other areas of the world. Placentophagy has a long history and has been practiced in many regions of the world. However, few scientific studies of the medicinal value of placental extract have been conducted [8]. Dried human placenta, also known as "Zi He Che", was used in sixteenth-century China as a cure for impotence and for infertility, liver, and kidney issues, according to Li Shizen's "Compendium of Materia Medica" [9]. It was also used to boost

**Citation:** Chou, M.-Y.; Yang, C.-P.O.; Li, W.-C.; Yang, Y.-M.; Huang, Y.-J.; Wang, M.-F.; Lin, W.-T. Evaluation of Antiaging Effect of Sheep Placenta Extract Using SAMP8 Mice. *Processes* **2022**, *10*, 2242. https://doi.org/ 10.3390/pr10112242

Academic Editors: Hah Young Yoo and Tao Sun

Received: 18 August 2022 Accepted: 25 October 2022 Published: 1 November 2022

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energy and stamina. The Araucanian Indians of Argentina use dried umbilical cord ground into powder to heal sick children. The Kol tribe in Central India consumes the placenta to enhance reproductive function [10].

In mainland China, since the Tang dynasty, practitioners of traditional Chinese medicine (TCM) have valued the placenta as a transitory organ that sustains the growth and development of a fetus in utero [11]. TCM practitioners have used the placenta to reduce mental tension and anxiety, enrich the blood, tonify Qi, increase essences, reduce fatigue and spasm, and detoxify the body [12]. In recent times, increased interest in the pharmacological effects and therapeutic value of the human placenta has led to more scientific studies, as well as increased usage in clinical settings [13].

Placenta treatment is now used for a variety of conditions, including adrenocortical hypofunction, lumbago, compromised immunity, infertility, depression, lack of lactation, and hair loss, as well as for antiaging purposes [9]. Within conventional medicine, practitioners are increasingly acknowledging the effectiveness of human placenta treatment, although restricted availability has prevented its widespread use to date. The benefits of treatment with sheep placenta (SP) extract include blood and skin nourishment, sedation effects, and increased longevity [14]. SP extract is one of the best medications for boosting essential vitality. Practitioners favor the use of sheep placenta because it shares the same nutritional composition and pharmacological properties as the human placenta [15]. However, fatigue in mice was also relieved by preparations made from goat placenta [16]. SP extract (SPE) is rich in tiny molecular peptides, nucleic acids, enzymes, amino acids, growth factors, collagen, and other active ingredients that may boost immunity, and reduce the effects of hypoxia [17].

The senescence-accelerated mouse (SAM) is a naturally occurring experimental mouse breed that exhibits early aging characteristics such as senile amyloidosis, senile osteoporosis, cataracts, a suppressed immune system, and deficiencies in learning and memory [18,19]. Breeders have developed a number of senescence-prone (SAMP) and senescence-resistant (SAMR) lines. Due to the early onset of brain shrinkage, which is accompanied by learning and/or memory impairment and affective disturbances, SAMP8 is a commonly utilized strain, particularly in dementia- and aging-related studies [20]. The longevity of SAMP8 is roughly half that of SAMR1 [21].

Integrative biological medicine is important for managing and restoring health and fitness. Placental extracts that still retain active components may promote rejuvenation, revitalization, and the restoration of youth and vitality by delaying aging processes. The placental extract is a powerful therapeutic agent with effective regeneration abilities that counter the aging process. In the present study, we evaluated the antiaging effect of SPE in SAMP8 mice.
