Evaluation of Antimicrobial, Antioxidant, Total Phenolic, Total Flavonoids, Metal Content and Proximate Potential of Solanum xanthocarpum L. (Solanaceae)

Abstract

AbstractThe current research work is focused on screening of antimicrobial, antioxidant, total phenolic, total flavonoid, metal estimation and proximate potential of four parts (fruits, leaves, stem bark and root bark) of S. xanthocarpum. Antimicrobial potential of dried crude extracts of S. xanthocarpum were evaluated against two gram positive bacteria (S. aureus, P. vulgaris), three gram negative bacteria (P. aeruginosa, K. pneumonia, E. coli), three fungi (A. flavus, F. solani, stolonifer) and two yeasts (S. cerevisiae, C. albicans) by using disc diffusion assay. Five organic solvents ranging from non-polar to highly polar were used for extraction of active metabolites. Amongst all the parts of S. xanthocarpum tested, antimicrobial activity of methanol extract of fruits (14.67±0.33) against P. aeruginosa, ethanolic extract of leaves against P. vulgaris (14±0.58), stem bark methanolic extract against S. aureus (13±0.58) and stem bark methanolic extract against P. vulgaris (17.67±0.33) were found to be more significant. All other extracts also showed promising antimicrobial activity against bacterial pathogens. Among fungal pathogens, R. stolonifer and S. cerevisiae were found to be more sensitive to extracts of S. xanthocarpum. Gram negative bacteria exhibited more resistance than gram positive bacteria. However, fungi were found to be more resistant than bacteria. All the extracts showed antioxidant activity. However, methanol extract of stem bark of S. xanthocarpum with IC50 value of 0.323102 mg mL−1 showed maximum antioxidant potential. Total phenolic contents ranged from 12.3541±1.73 to 23.2942±1.33 Pmol GA/ug. However, highest flavonoid content was found in the stem bark extract (17.8480±1.75 ugRutin/ug) and lowest in leaves extract of S. xanthocarpum (2.4806±0.59 ugRutin/ug). Total metal contamination in four parts of Solanum xanthocarpum (fruits, leaves, stem bark and root bark) was estimated by atomic absorption spectroscopy and results showed Cadmium contamination in its stem bark and root bark, Chromium contamination in leaves, stem bark and root bark, Copper and Magnesium contamination in all parts of S. xanthocarpum and Maganese contamination in leaves critically above the standard permissible limits. The proximate analysis of the Solanum xanthocarpum revealed that stem bark is a poor source of lipid (3.42%) and high carbohydrate (50.07%) and ash (16.50%) contents. Whereas, root bark has highest wet moisture content (65%), dry moisture content (20%) and lowest fiber (13%). Highest energy (285.455%), protein (8.32%), fat (9.79%) and lowest amount of ash (13%) was found in fruits. This composition shows that the Solanum xanthocarpum could be considered as a good source of carbohydrate, moisture and energy. These results revealed that over all, methanolic extract of the S. xanthocarpum is richest in phenolic, flavonoid and nutritional contents as well as most potent against bacterial and fungal pathogens. Therefore, further investigation is recommended to isolate, screen and characterize their active metabolites.