Biopotentiality of leaf and leaf derived callus extracts of Salacia macrosperma Wight. — An endangered medicinal plant of Western Ghats

Abstract Standardization of protocol for induction of callus in Salacia macrosperma Wight was achieved with 98% in combination of 2, 4-dichlorophenoxyacetic acid and benzylaminopurine at 2.5 ± 1.5 mg mL−1 concentrations. This was followed by sequential solvent extraction of leaf and its callus and then subjected for phytochemical analysis. The biochemical test revealed the presence of varied classes of phytoconstituents both in leaf and callus extracts. The antimicrobial activities of the crude extracts showed significant inhibition against tested pathogens. The methanol leaf extract offered maximum inhibition against E. coli (15.50 mm), Salmonella typhi (17.33 mm), Staphylococcus aureus (15.50 mm), Bacillus subtilis (17.16 mm), Pseudomonas aeruginosa (16.66 mm). The inhibition against fungal pathogens like Aspergillus flavus (13.66 mm), Fusarium oxysporum (15.63 mm), F.moniliforme (17.53 mm) and Candida albicans (16.10 mm) and no activity was observed in hexane and petroleum ether extracts. The MIC range between 0.312–2.5 mg mL−1, which was further confirmed by cell viability test and changes in cellular morphology, was observed by scanning electron microscope upon treatment. Likewise, total phenolic, flavonoid contents and antioxidant properties by DPPH assay, nitric oxide scavenging, phosphomolybdenum and reducing power assay were carried out and all the extracts employed significant results in a dose-dependent manner. Further, a haemolytic test revealed anti-haemolysis of 5.24% and 2.89% respectively at higher concentration (500 μg mL−1) in leaf and callus methanol extracts without negative effects on human erythrocytes. Overall the results stated that higher bioefficacy was observed in leaf extracts than a callus. Thus, employment of tissue culture strategy helps in order to enhance the bioactive metabolites of interest and also to conserve endangered medicinal plants.