Pharmacological activities of leaf and bark extracts of a medicinal mangrove plant Avicennia officinalis L

Background Avicennia officinalis is a medicinally important mangrove plant and used in traditional medicinal practices to treat various ailments like rheumatism, paralysis, asthma, dyspepsia, tumors etc. The objective of the present study was to evaluate the carbohydrate metabolizing enzyme inhibitory, antioxidant, antimicrobial and cytotoxic potentials of ethanol leaf and bark extracts of A. officinalis. Methods The carbohydrate metabolizing enzyme inhibition potential was studied by α-amylase and α-glucosidase inhibitory activities. The antioxidant activity was investigated by measuring the scavenging potential of extracts against DPPH, ABTS and superoxide radicals. The antimicrobial activity was studied by agar well diffusion method and the cytotoxicity potential by MTT assay. Results The study revealed that A.offiicnalis bark extract inhibited the activity of α-amylase and α-glucosidase in a dose dependent manner with an IC50 value of 0.66 and 0.71 mg/ml respectively. The leaf extract also demonstrated inhibition potential against α-amylase and α-glucosidase with an IC50 value of 0.29 and 1.19 mg/ml respectively. The ethanol bark extract also exhibited scavenging potential against DPPH, ABTS and superoxide radicals in a dose dependent manner with IC50 values of 112, 114 and 82 μg/ml respectively and ethanol leaf extract with IC50 values of 200, 41.9 and 207.6 μg/ml respectively. Both leaf and bark extracts exhibited dose dependent antiproferative activity on TC1 murine cell lines. Both leaf and bark extracts exhibited antimicrobial activity against bacteria (Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and fungi (Candida albicans, C. krusei). The qualitative phytochemical assay, UV-Vis and FTIR analysis revealed the presence of different phytoconstituents in the leaf and bark extracts of A.officinalis. Conclusion The results suggest that ethanol leaf and bark extracts of A.officinalis were effective in inhibiting α-amylase and α-glucosidase and also have antioxidant, antimicrobial potentials which justify the ethnobotanical use of this plant.