plants Review Potential Application of Some Lamiaceae Species in the Management of Diabetes Ninon G.E.R. Etsassala 1 , Ahmed A. Hussein 2 and Felix Nchu 1, *   Citation: Etsassala, N.G.E.R.; Hussein, A.A.; Nchu, F. Potential Application of Some Lamiaceae Species in the Management of Diabetes. Plants 2021, 10, 279. https://doi.org/10.3390/plants 10020279 Academic Editors: Ana Maria Carvalho and Laura Cornara Received: 17 November 2020 Accepted: 26 January 2021 Published: 1 February 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Horticultural Sciences, Faculty of Applied Sciences, Cape Peninsula University of Technology, Symphony Road, Bellville 7535, South Africa; 3415216@myuwc.ac.za 2 Chemistry Department, Cape Peninsula University of Technology, Bellville Campus, Symphony Road, Bellville 7535, South Africa; mohammedam@cput.ac.za * Correspondence: felixnchu@gmail.com; Tel.: +27-219-596-473 Abstract: Diabetes is one of the most dangerous metabolic disorders, with high rates of mortality worldwide. Since ancient times, medicinal plants have been used in traditional medicine to treat many diseases, including diabetes and its related complications. Plants are widely accepted, affordable, and perceived to have minimal adverse side effects. The Lamiaceae family is a potential source of therapeutic agents for the management of metabolic disorders, including diabetes. Hence, this review paper summarizes the antidiabetic use of Lamiaceae species in folk medicine globally. Furthermore, we present the antidiabetic activities and phytochemical constituents of twenty-three (23) Lamiaceae species and the antidiabetic activity of some notable chemical constituents isolated from some of these Lamiaceae species. Keywords: Lamiaceae species; diabetes mellitus; oxidative stress; secondary metabolites 1. Introduction Diabetes mellitus (DM) is one of the most dangerous metabolic disorders, causing high mortality rates worldwide [1]. It is well known that insulin plays a crucial role in glucose homeostasis, as it activates the transport of blood glucose inside the skeletal muscle [2]. However, insulin resistance in target tissues and the shortage of insulin production from pancreatic β-cells are the principal attributes of type 2 diabetes. Additionally, type 2 DM characterization also encompasses a decrease in peripheral glucose uptake within the muscle, adipose, or liver cells and an increase in endogenous glucose secretion, causing increased blood glucose concentration [3–5]. Therefore, agents with the ability to activate glucose uptake in these tissues can ameliorate insulin resistance and treat diabetes [6]. Many synthetic antidiabetic drugs such as acarbose, sulfonylurea, miglitol, metformin, and thiazolidinedione are already present in the market. However, their effectiveness is restricted because of their high cost and adverse side effects [7,8], which incentivize the development of powerful natural antidiabetic products/drugs with minimal adverse side effects. Lamiaceae, commonly known as the mint family, is a cosmopolitan flowering plant family with approximately 7136 species assigned to 236 genera. Most of the species are herbaceous or shrubby, and trees are scarce. The most well-known genus is Salvia (900), followed by Scutellaria (360), Stachys (300), Plectranthus (300), Hyptis (280), Teucrium (250), Vitex (250), Thymus (220), Nepeta (200), and Clerodendrum (150) [9]. The family possesses significant economic value, as it contains some horticultural species and culinary herbs, such as rosemary, salvia, ocimum, and leonotis. They are well reputed because of the high level of aromatic compounds within their leaves, flowers, and essential oils. These compounds are pharmacologically active terpenoids that play vital roles in developing new bioactive products within the cosmeceuticals, nutraceuticals, Plants 2021, 10, 279. https://doi.org/10.3390/plants10020279 https://www.mdpi.com/journal/plants