Morphological and microscopic evaluation of Nephelium mutabile blume

Nephelium mutabile Blume, commonly known as Pulasan, is a tropical fruit in Southeast Asia and belongs to the Sapindaceae family. This study aimed to elucidate the morphological and microscopical characteristics of Pulasan’s leaves and stems. Fresh samples of leaves and stems were collected, authenticated, and analysed following WHO guidelines. The morphological evaluation revealed distinctive characteristics of the leaves and stems, including their shape, size, colour, and texture. The upper surface of the leaf was observed to be dark green, while the lower surface was light green, exhibiting a glossy texture and a lanceolate form. The stem exhibited a light brown colour and a smooth texture. Microscopical evaluation of leaf lamina, petiole and stem was carried out. The leaf lamina was found to be dorsiventral in nature. In petiole transverse section, the outer epidermal and palisade layers of leaf were modified into cork and cortex layers. The midrib of lamina and petiole showed conjoint collateral closed-type vascular system. The transverse section of stem showed woody structure with xylem fibres and vessels. Pharmacognostical evaluation of a crude drug is always essential for its identification, authentication and standardisation. Both morphological and microscopical evaluation methods are the initial phases in the evaluation of a crude drug. So, the results from the present study offered important insights into the identification and standardisation of this unexplored species.