**4. Conclusions**

The metabolites produced by *S. californicus* ADR1 had shown very low MIC90 values against a range of Gram-positive pathogens including those notified by the WHO as high priority pathogens. This suggested that it could be an excellent source for effective anti-infective compounds against some of the most challenging pathogens like *S. aureus*, MRSA, *S. epidermis, E. faecalis* and *E. faecium*. The ADR1 metabolites came across as potent inhibitors of biofilms of both methicillin-sensitive and methicillin-resistant strains of *S. aureus*. Along with the antimicrobial activity, the metabolites exhibited good antioxidant activity. Antioxidant property with no haemolytic activity indicated the potential of ADR1 metabolites for use as antioxidants. The above bioactivities could be attributed to the presence of several therapeutically significant class of compounds as revealed by the biochemical profiling and the GC-MS analysis. These constituents, individually or in combination, may account for the pharmacological actions of the extract. Low SI for several compounds in the ADR1 metabolite preparations was noteworthy as it indicated greater possibility of finding novel molecules.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2076-2607/8/6/929/s1, Figure S1: GC-MS Chromatogram of ADR1 metabolites; Table S1: Compounds detected in the ADR1 metabolites extract by GC-MS analysis using NIST & Wiley library as reference.

**Author Contributions:** A.K.D. has conceptualized the research project and guided the experimental work. R.S. has carried out the experiments and prepared the initial draft of the manuscript, which was corrected and finalized by A.K.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors acknowledge the administrative and material support given by the Netaji Subhas University of Technology, New Delhi to carry out this work. Research fellowship to RS by NSUT is duly acknowledged. Services of Advanced Instrumentation Centre, Jawahar Lal Nehru University, New Delhi for GC-MS analysis, is duly acknowledged.

**Conflicts of Interest:** The authors declare no conflict of interest.
