Micromorphological and Phytochemical Evaluation of <i>Heliotropium rariflorum</i> Stocks From Karak, Pakistan

Micromorphological and phytochemical studies play a major role in quality control and standardization of traditional or herbal medications. In the present research, micromorphological assessment of Heliotropium rarifloum stocks was performed through light and scanning electron microscopies (LM & SEM). The anatomy of leaves, stem and root showed salient histological features. Both surfaces of the leaves had setose glandular trichomes measuring 20-38 × 6-15 µm. The lower epidermis had comparatively a maximum anomocytic stomata (16-35) and stomatal index (12-33). The mature pollen grains were small (74 µm) and spheroidal shaped, with psilate exine (2 μm) sculpturing. Vein termination and vein islet number of the upper epidermis were 5-20 and 5-15, respectively. The palisade ratio of the leaf lamina for the upper and lower epidermis was 2-10 and 2-8. LM and SEM of the powdered samples displayed crystals, phloem fibers, xylem, vessels, sieve tube elements, companion cells, and tracheids. Extractive values determination, fluorescence, and phytochemical analysis were employed for quality control according to the World Health Organization (WHO) guidelines. Phytochemical screening revealed various secondary metabolites. It is suggested that H. rariflorum might be a reliable source of nutrients and secondary metabolites and might be more medically effective. The current findings confirm its standardization and validation.