A Study on Physiochemical, Microscopical and Total Alkaloids, Phenolic Contents of Methanolic Extract of Proboscidea louisianica Leaves

Proboscidea louisianica is a medicinal plant traditionally employed for therapeutic purposes, yet limited pharmacognostic and phytochemical data exist on its leaves. This study aimed to evaluate its diagnostic features, physicochemical constants, phytochemical profile, and potential information for quality control and pharmacological exploration. Shade-dried leaf powder was subjected to macroscopic and microscopic analysis, preliminary phytochemical screening, and quantitative determination of alkaloids and phenolics. Microscopic studies revealed key diagnostic markers, including unicellular and multicellular trichomes, lignified fibres, compactly arranged parenchyma cells, prismatic and cluster crystals of calcium oxalate, and six to seven collateral vascular bundles in the midrib. Physicochemical analysis showed total ash (0.81%), swelling index (3%), and loss on drying within acceptable pharmacopoeial limits, confirming purity of the crude drug. Phytochemical screening demonstrated the presence of alkaloids, tannins, phenols, saponins, steroids, proteins, and glycosides, while flavonoids were absent. Quantitative estimations indicated an alkaloid content of 0.638% and total phenolic content of 5.84 mg gallic acid equivalents per gram of dried leaf material, highlighting its antioxidant potential. These findings establish essential pharmacognostic and phytochemical standards for P. louisianica leaves and support their role as a natural source of antioxidant compounds with therapeutic relevance. Further studies on isolation of active principles and biological evaluation are recommended.