Anatomical and Physicochemical Attributes of Endemic Medicinal Plant Species <i>Vincetoxicum capparidifolium</i> (Wight &amp; Arn.) Kuntze, Apocynaceae

Vincetoxicum capparidifolium (Wight & Arn.) Kuntze [=Tylophora capparidifolia (Wight & Arn.) Kuntze], belonging to the family Apocynaceae, is a medicinal plant species endemic to the southern Western Ghats, Tamil Nadu, India. The current study sought to investigate the macroscopic, organoleptic, microscopic, physicochemical, and proximate compositional aspects of the fresh and powdered leaf and stem portions of V. capparidifolium. The anatomical peculiarities of the leaf parts reveal a hypostomatic nature with paracytic stomata, the epidermis being made up of thin-walled cells covered with a thick cuticle (5.9 μm), and the hypodermis comprising angular collenchyma cells. The petiole is oval/rounded-ellipse with abundant nonglandular multicellular trichomes ascending from the epidermis. The hypodermis is composed of collenchymatous cells containing many calcium oxalate crystals and silica bodies. Bicollateral vascular bundles with internal and external phloem characterize the leaf, stem, and petiole parts. The stem is covered by a thin cuticle, chlorenchymatous hypodermis, and large gelatinous fiber bundles (124.29 × 81.71 μm). Secondary growth in the stem is characterized by the development of periderm and lignified vascular tissues. Bicollateral vascular bundles are overlaid by irregular sclerenchyma patches (7.07 × 5.36 μm), a parenchymatous cortex, and pith composed of thin-walled parenchyma cells. Scanning electron microscopic study of powdered plant parts disclosed the presence of fiber in the stem and a trace outline of leaf epidermal cells. X-ray diffraction analysis specified indefinite crystallinity in the plant powder (57.038-69.500 nm). Thorough examination of pH, ash content, and percentage of crude lipid confirms that V. capparidifolium exhibits sufficient quality and purity.