Secondary Metabolites, Antioxidant, and Antiproliferative Activities of Dioscorea bulbifera Leaf Collected from Endau Rompin, Johor, Malaysia

Ethnobotany, Phytochemistry, and Pharmacological Activity of Dioscorea bulbifera: A Comprehensive Review

Dioscorea bulbifera (Family: Dioscoreaceae) also referred to as 'Air potato,' carries significant importance in the traditional medicine of China, West Africa and India. It is a common ingredient in numerous herbals and Ayurvedic formulations used to treat a variety of ailments. The literature review extensively examined the historical usage, phytoconstituents, characterisation of phytoconstituents, and medicinal uses of tubers, leaves, rhizomes and bulbils, with a particular focus on comparing research findings. Among the bioactive constituents, aglycone forms of steroidal saponins such as dioscorine, dioscin, diosbulbins, and diosgenin exhibit significant biological activities. Extracts from different parts of the plant exhibited pharmacological activities like anti-viral, anti-malarial, analgesic, antidiabetic, and anticancer. It is necessary to conduct an in-depth investigation to bridge between traditional knowledge and scientific evidence. This comprehensive review aims to provide a detailed understanding of the ethnobotany, phytoconstituent, chemical characterization and pharmacological potential of D. bulbifera, highlighting its prospects and challenges for future research and medicinal application.

Dioscorea spp.: Comprehensive Review of Antioxidant Properties and Their Relation to Phytochemicals and Health Benefits

Dioscorea, consisting of over 600 species, is the most important genus in the Dioscoreaceae family; however, the practically used plants, which are commonly called yam, are restricted to a remarkably smaller number of species. Numerous studies have reported the high nutritional value of yam, particularly as an alternative source of starch and some important micronutrients. Several Dioscorea species are widely used for various medicinal purposes as well. In many studies, the bioactivities and health benefits of Dioscorea extracts and other preparations have been related to the presence of phytochemicals, which possess antioxidant properties; they are related mainly to radical-scavenging capacity in chemical assays and positive effects on the endogenous antioxidant system in cell-based and in vivo assays. Considering the increasing number of publications on this topic and the absence of comprehensive and focused review papers on antioxidant potential, this article summarizes the results of studies on the antioxidant properties of Dioscorea spp. and their relation to phytochemicals and health benefits. A comprehensive survey of the published articles has revealed that the majority of studies have been performed with plant tubers (rhizomes, roots), while reports on leaves are rather scarce. In general, leaf extracts demonstrated stronger antioxidant potential than tuber preparations. This may be related to the differences in phytochemical composition: saponins, phenanthrenes and, for some pigment-rich species (purple yams), anthocyanins are important constituents in tubers, while phenolic acids and flavonoids are characteristic phytochemicals in the leaves. The review may assist in explaining ethnopharmacological knowledge on the health benefits of Dioscorea plants and their preparations; moreover, it may foster further studies of poorly investigated species, as well as their wider application in developing new functional foods and nutraceuticals.

Anti-inflammatory norclerodane diterpenoids and tetrahydrophenanthrene from the leaves and stems of Dioscorea bulbifera

Chemical investigation of the leaves and stems of Dioscorea bulbifera resulted in isolation of 10 compounds, including three new norclerodane diterpenoids, diosbulbiferins A (1) and B (2) and diosbulbiferinoside A (3), and one new natural congener, diosbulbiferin C (4), along with one new tetrahydrophenanthrene, diosbulbinone (8). Their structures were elucidated by comprehensive analyses of spectroscopic methods, including NMR and mass spectra. The absolute configurations of compounds 1-3 and 8 were deduced by time-dependent density functional theory (TD-DFT) electronic circular dichroism (ECD) spectroscopic analyses. In addition, cytotoxic effects against MCF-7, HepG2, and SK-Mel-2 cancer cells and in vitro anti-inflammatory effects of the isolated compounds in LPS-stimulated BV2 microglial cells were also reported.