Isolation, characterization, and analysis of pure compounds from Leea macrophylla leaf extract for antibacterial, antidiabetic, cytotoxicity and phytotoxicity

Abstract

This research aims to isolate, characterize, and analyze pure compounds from Leea macrophylla leaf extract to investigate its antibacterial, antidiabetic, cytotoxic, and phytotoxic effects. Fresh leaves were collected, dried, and subjected to methanol extraction to obtain a crude extract. From the petroleum ether fraction (PEF) of this extract, three fractions—designated LM1, LM2, and LM3—were prepared using column chromatography. The fractions were tried to be characterized in search for single compound by instrumental technique like ATR-FTIR, ¹H NMR and ¹³C NMR but the ¹H NMR and ¹³C NMR spectra were found complex which were difficult to interpret. To dispel the doubt and get clear idea about the structure, GC-MS analysis of the compounds was carried out whose result showed that all the three extracts were decomposed to several small organic compounds that made the structure elucidation difficult. For this complication, the characterization of the extracts was not possible. Numerous compounds were identified in the methanol extract of L. macrophylla through GC-MS analysis. Among these compounds, Benzene, 1,2,3-trimethyl- and Undecane were found in higher percentages in LM1. LM2 contained Azulene and Bicyclo [4.4.1]undeca-1,3,5,7,9-pentaene, while LM3 was characterized by the presence of 9,9-Dimethoxybicyclo [3.3.1]nona-2,4-dione and 11-(2-Cyclopenten-1-yl)undecanoic acid, among others. The antibacterial activity of these fractions was evaluated against various bacterial strains, demonstrating broad-spectrum effectiveness. LM1 fraction showed the highest antibacterial activity against Proteus sp. With zone of inhibition 25 mm and weak activity against S. sonnei with zone of inhibition 5 mm. LM2 showed the highest activity to both E. cocci and P. aeruginosa with the zone of inhibition of 18 mm and comparatively lower but significant against Proteus sp. LM3 was highly active to S. sonnei with zone of inhibition 20 mm and lower but quite significant against Proteus sp. Moreover, the anti-diabetic potential was assessed, with LM1 showing the strongest α-amylase inhibitory activity, outperforming quercetin (standard). The IC50 values of LM1, LM2, LM3, and quercetin were 57.36 μg/mL, 100.66 μg/mL, 164.92 μg/mL, and 97.45 μg/mL, respectively. In addition, cytotoxicity was assessed using a brine shrimp lethality bioassay, and phytotoxicity was evaluated through seed germination and growth assays. The results suggest that L. macrophylla leaf extracts have potential applications in antimicrobial, antidiabetic, and anti-cancer contexts. This comprehensive study bridges gaps in knowledge surrounding L. macrophylla's multifaceted properties, offering insights into its therapeutic and ecological potential for healthcare and environmental management.