Inter-and intra-species variation for agronomic, chemical, and anti-diabetic properties among Ocimum species

Title : Inter-and intra-species variation for agronomic, chemical, and anti-diabetic properties among Ocimum species

Abstract:

Plant products have long been used for diabetes prevention and treatment worldwide. Among them, Ocimum species have shown effectiveness in clinical trials for their antidiabetic properties. However, knowledge of these species, their antidiabetic activity, and chemical profiles in the USA remains limited. This study evaluated 16 accessions from six Ocimum species (O. aficanum, O. americanum, O. bailicum, O. campechianum, O. gratissimum, and O. tennuiflorum) for growth, chemical composition, and antidiabetic activity. Growth variables included plant height, number of branches, and above-ground biomass. Antidiabetic activity was assessed using an α-glucosidase inhibitory assay with methanolic leaf extracts, using acarbose, a popular medicine for treating Type-2 diabetes, as a positive control. Chemical profiles were analyzed by quantifying fourteen compounds, including flavonoids, phenols, and terpenoids. Significant variations (p ≤ 0.05) were observed in growth among the accessions. Plant height ranged from 24.5 cm (O. basilicum PI 172996) to 54 cm (O. gratissimum PI 21171), while above-ground biomass ranged from 141.5 g (O. basilicum PI 652071) to 365.8 g/plant (O. basilicum PI 358472). The O. basilicum and O. campechianum accessions displayed mild α-glucosidase inhibition (14% and 19%), whereas O. gratissimum PI 500952 showed 80% inhibition, comparable to acarbose. Key compounds in O. africanum and O. americanum included ursolic acid, oleanolic acid, and rosmarinic acid, while O. basilicum and others showed higher levels of syringic acid and eugenol. Notably, rosmarinic acid (5.7%) and caffeic acid (0.6%) were significantly higher (p < 0.0001) in O. gratissimum PI 500952, correlating with its maximum α-glucosidase inhibition. This study highlights the potential of O. gratissimum for its antidiabetic properties and introduces methods for assessing the chemical composition and agronomic performance of different Ocimum varieties. The findings support the development of sustainable organic production systems for commercially viable Ocimum species with known bioactivity.

Biography:

Dr. Srinivasa Rao Mentreddy, an Indian-born American citizen, is a Professor of crop science at Alabama A&M University, Alabama, USA. His research focuses on developing cover crop-based sustainable crop production practices for vegetable and medicinal herbs in the open field and agroforestry systems, evaluating low-temperature plasma for ensuring food safety and improving crop productivity, and climate-smart agricultural practices using cover crops and alley cropping. Dr. Mentreddy earned a BS and MS in Agriculture from the Andhra Pradesh Agricultural University, India, and a Ph.D. in Agronomy from the University of Tasmania, Australia. Dr. Mentreddy is well-published, with about 48 peer-reviewed journal articles, five book chapters, and more than 196 conference proceedings abstracts.