Phytochemical Analysis, Antimicrobial and Anti-Inflammatory Efficacy of Leucas aspera Leaf Extracts

Medicinally, Leucas aspera has been confirmed to comprise broader pharmacological effectiveness viz., antioxidant, insecticide, antipyretic, chronic rheumatism, and cytotoxic activity etc. This plant is traditionally used in the treatment of common infections viz., sore eyes and nose, fever, cough, skin eruptions, cold, wounds and sore throat. In this study, we intended to screen the phytochemical constituents, evaluate the antimicrobial and anti-inflammatory capacities of different solvent extracts of Leucas aspera leaves. Leucas aspera leaves were collected, shade dried, fine powdered and subjected to phytochemical extraction using methanol, ethanol, water and hydroalcohol. From the extracts, phenolic content was estimated by Folin-Ciocalteau reagent method followed by antimicrobial activity by Kirby-Bauer and Micro dilution assay with four different pathogenic bacteria. Later, anti-inflammatory activity was performed by various enzymatic assays. Phytochemical screening of Leucas aspera extract confirmed the presence of alkaloids, flavonoids, phenols, and tannins. The hydroalcoholic (MIC:12.5 µg/ml; MBC: 25µg/ml) and ethanolic (MIC:6.25 µg/ml; MBC:12.5 µg/ml) extracts presented effective and potent antimicrobial activity against Escherichia coli, Staphylococcus aureus, Streptococcus mutants, and Propionibacterium acne. Among the in vitro anti-inflammatory assays, hydroalcoholic extracts offered effective albumin denaturation (183.8±31.6µg/ml), heat induced hemolysis (213.4±22.3µg/ml) and considerable hypotonicity induced hemolysis (277.8±29.9µg/ml). The results were expressed as mean ± standard deviation, and statistical interpretation was based on two- tailed tests at a p ≤ 0.05 significance level. In this current study, it was observed that Leucas aspera holds a variety of valuable secondary metabolites, which includes strong antimicrobial and anti-inflammatory activities, however further studies are necessary to assess its therapeutic use. Based on the existing experiments, corresponding results may set the foundation for future research.