Background and Objective:
Chronic diseases are associated with low-grade inflammation
and oxidative damage. Traditional medicines have been used to manage these disorders due to their
high polyphenol content and potent antioxidant activity. We evaluated the in-vitro anti-diabetic and
antioxidant potential of extracts of several medicinal plants namely, Mangifera indica, Terminalia
arjuna, Moringa oleifera, Albizia lebbeck, Terminalia chebula and Hippophae rhamnoides.
Methods:
Total polyphenol, flavonoid, and saponin contents were estimated by standard methods.
Antioxidant activity was measured using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging
assay. The anti-diabetic potential was evaluated using in-vitro α-glucosidase inhibition assay.
Results:
Terminalia chebula was found to be the richest in both polyphenols (566.5 ± 21.9 μg Gallic
acid equivalents/mg of dry weight) and flavonoids (190.67 ± 10.78 quercetin equivalents/mg of dry
weight). Extract of Terminalia arjuna was the richest source of saponins (171.92 ± 12.48 μg saponin
equivalents/mg of dry weight). All plant extracts showed potent anti-oxidant activity as reflected by
their IC50 values in DPPH assay, with Albizia lebbeck (IC50 = 1.35 μg/ml) being the most potent. All
plant extracts also showed potent anti-diabetic activity as inferred from their ability to inhibit α-
glucosidase, the principal enzyme involved in the metabolism of dietary carbohydrates in the intestine.
It was observed that all tested extracts were more potent (IC50 2.53 to 227 μg/ml) in comparison
to the standard α-glucosidase inhibitor Acarbose (IC50=2.7 mg/ml).
Conclusions:
The plant extracts of Mangifera indica, Terminalia arjuna, Moringa oleifera, Albizia
lebbeck, Terminalia chebula, and Hippophae rhamnoides possess potent antioxidant and α-
glucosidase inhibitory potential and can aid in the management of postprandial hyperglycemia and
oxidative damage.
Evaluation of Antimicrobial Activity of Extracts of Terminalia chebula and Piper nigrum against Streptococcus mutans: An In Vitro Study
