Antimicrobial activity and structure elucidation of Pterosterone, a naturally occurring phytoecdysteroid isolated from the leaves of Vitex madiensis Oliv. (Lamiaceae)

Abstract

Background

Traditional uses and preliminary studies suggested that extracts from the leaves of Vitex madiensis might contain bioactive compounds with medicinal value.

Purpose

This study aimed to isolate and identify bioactive compounds from the leaves of V. madiensis and evaluate their antimicrobial activities. Additionally, the study sought to elucidate the structure of the isolated compound using spectroscopic methods and assess its stability and interactions with enzyme receptors through in silico studies.

Study design

Compounds were isolated from the ethyl acetate extract of V. madiensis leaves and evaluated for antibacterial and antifungal activities. The isolated compound underwent in silico studies to determine its stability, sensitivity, and interaction with enzyme receptors.

Methods

Leaves of V. madiensis were extracted with ethyl acetate, followed by chromatographic techniques to isolate the target compound. Antibacterial and antifungal properties were tested, determining minimum inhibitory concentration (MIC) values against bacterial and fungal strains. Stability, kinetic sensitivity, and interactions with β-lactamase and Sterol-14-alpha demethylase were assessed using computational methods. Structural elucidation was achieved using NMR, MS, IR, and literature comparisons.

Results

The isolated compound exhibited antibacterial (MIC=1000–15.6 µg/mL) and antifungal (MIC=1000 µg/mL) activities. In silico studies showed it is stable, has high kinetic sensitivity, and affinity with enzyme receptors (β-lactamase, ΔG= −8.16 kcal/mol; Sterol-14-alpha demethylase, ΔG= −8.56 kcal/mol). The compound was non-toxic and non-mutagenic.

Conclusion

The study isolated Pterosterone from V. madiensis leaves, demonstrating significant antibacterial and antifungal activities. Its non-toxic and non-mutagenic profile suggests potential as a natural antimicrobial agent. This is the first report of pterosterone from Vitex madiensis.