Phytochemical content, antioxidant activities and androgenic properties of four South African medicinal plants

Introduction: This study aimed to investigate the phytochemical contents, antioxidant activities and androgenic properties of Peltophorum africanum Sond, Trichilia emetica Vahl, Terminalia sambesiaca, and Ximenia caffra. Methods: The finely powdered leaves of the selected plants were extracted using acetone, aqueous and methanol as solvents. The total phenolics and flavonoids contents were determined from gallic acid and quercetin standard curves. The antioxidant activities of these extracts were evaluated using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay. The effects of plant extracts (100-1000 μg/mL) on TM3 Leydig cells were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay. Testosterone levels were measured using ELISA kit. Results: The methanol extracts of T. sambesiaca and X. caffra revealed higher total phenolic and flavonoid contents (102.13 ± 2.32 mg/g gallic acid equivalent and 1.05±0.04 mg/g quercetin equivalent, respectively) than other plant extracts. The acetone and methanol extracts of P. africanum revealed the best IC50 values (12.50 ± 0.052 μg/mL) against DPPH compared to the other plant extracts and ascorbic acid. The MTT assay results showed that all concentrations of plant extracts maintained cell viability and were not cytotoxic with IC50 values of greater than 20 μg/mL. The methanol extract of T. sambesiaca had the higher testosterone production at 500 μg/mL (0.399 ng/mL) when compared with the basal control while at the concentration of 500 μg/mL the acetone extracts of P. africanum and T. sambesiaca had significantly high testosterone production of 0.147 and 0.188 ng/mL, respectively when compared with basal control. Conclusion: The results reveal that these plants possess antioxidants and androgenic properties and suggest the potential use for the treatment of male infertility.