Biological Studies of Some Selected Medicinal Plants from Kathmandu Valley and Isolation of Chemical Compounds
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Department of Chemestry
Abstract
The aim of this study is to investigate the phytochemical and biological
properties of some selected medicinal plants from Kathmandu valley and
isolation of phytoconstituents from active plant extract. The methanolic extracts
of Ageratina Adenophora, Cupressus sempervirens and Lantana camara aerial
parts were analyzed for their phytochemical analysis, toxicity test, antioxidant
activity, total phenolic and total flavonoid content, antidiabetic properties and
isolation of chemical constituents from active plant fraction and FTIR analysis.
The toxicity test was studied by brine shrimp lethality test. The antioxidant
potential was evaluated by DPPH radical scavenging assay. The amount of total
phenolic and flavonoid was estimated with the Folin-Ciocalteu reagent and
aluminium chloride method, respectively. The α amylase enzyme inhibition
activity was performed to evaluate the inhibition percentage for each extract.
The phytochemical analysis showed the presence of various secondary
metabolites like alkaloids, flavonoids, carotenoids, coumarins, glycosides,
polyphenol, carbohydrate, saponin, tannins, terpenoids, quinones, and volatile
oil & fats. The methanolic extracts of Ageratina adenophora was found to be
cytotoxic against brine shrimp as shown by its LC50
value of 833.68 µg/mL. The
methanolic extracts of Lantana camara (106.179 ± 11.390 µg/mL) showed the
strongest DPPH radical scavenging activity as its IC50
values were close to
standard ascorbic acid (17.456 ± 0.822 µg/mL). Lantana camara showed the
highest phenolic (10.2 ± 0.343 mg GAE/g) and flavonoid content (1.872 ± 0.16
mg QE/g) respectively. In addition, Ageratina adenophora methanolic extracts
were found to inhibit enzymatic activity of α-amylase under in-vitro starch
digestion bioassay with the IC50
value of 1.843 ± 0.007 mg/mL. The FTIR
measurement revealed the presence of C=O, O-H and C-H stretching bands at
the functional group region.
Keywords: Phytochemical, antioxidant, phenolic, flavonoid, antidiabetic, αamylase.