Department of Biochemistry and Microbiology, Nelson Mandela University, Port Elizabeth, South Africa.
Food Funct. 2021 Feb 15;12(3):1020-1038. doi: 10.1039/d0fo02611e.
The antidiabetic potential of Aspalathus linearis has been investigated for over a decade, however, its characterisation remains incomplete with results scattered across numerous journals making the information difficult to compare and integrate. To explore whether any potential antidiabetic mechanisms for A. linearis have been neglected and to compare the suitability of extracts of green and "fermented" A. linearis as potential antidiabetic treatment strategies, this study utilised a comprehensive in vitro antidiabetic target-directed screening platform in combination with high content screening and analysis/cellomics. The antidiabetic screening platform consisted of 20 different screening assays that incorporated 5 well-characterised antidiabetic targets i.e. the intestine, liver, skeletal muscle, adipose tissue/obesity and pancreatic β-cells. Both the green and fermented extracts of A. linearis demonstrated very broad antidiabetic mechanisms as they revealed several promising activities that could be useful in combatting insulin resistance, inflammation, oxidative stress, protein glycation and pancreatic β-cell dysfunction and death - with a strong tendency to attenuate postprandial hyperglycaemia and the subsequent metabolic dysfunction which arises as a result of poor glycaemic control. The green extract was more successful at combatting oxidative stress in INS-1 pancreatic β-cells and enhancing intracellular calcium levels in the absence of glucose. Conversely, the fermented extract demonstrated a greater ability to inhibit α-glucosidase activity as well as palmitic acid-induced free fatty acid accumulation in C3A hepatocytes and differentiated L6 myotubes, however, further studies are required to clarify the potentially toxic and pro-inflammatory nature of the fermented extract.
南非叶的降血糖潜力已经研究了十多年，但由于研究结果分散在众多期刊上，使得信息难以比较和整合，其特性仍然不完整。为了探索南非叶是否有任何被忽视的潜在降血糖机制，并比较绿南非叶和“发酵”南非叶提取物作为潜在降血糖治疗策略的适宜性，本研究利用了一种全面的体外糖尿病靶点定向筛选平台，结合高内涵筛选和分析/细胞组学。该糖尿病筛选平台由 20 种不同的筛选测定方法组成，其中包含 5 种已充分研究的糖尿病靶点，即肠道、肝脏、骨骼肌、脂肪组织/肥胖和胰岛β细胞。绿南非叶和发酵南非叶提取物均表现出非常广泛的降血糖机制，因为它们显示出了几种有前途的活性，这些活性可能有助于对抗胰岛素抵抗、炎症、氧化应激、蛋白质糖基化和胰岛β细胞功能障碍和死亡——具有强烈的减轻餐后高血糖和随后由于血糖控制不佳而引起的代谢功能障碍的趋势。绿提取物在对抗 INS-1 胰岛β细胞中的氧化应激和增强无葡萄糖条件下的细胞内钙水平方面更为成功。相比之下，发酵提取物在抑制α-葡萄糖苷酶活性以及棕榈酸诱导的 C3A 肝细胞和分化的 L6 肌管中的游离脂肪酸积累方面表现出更强的能力，但需要进一步研究来阐明发酵提取物潜在的毒性和促炎性质。
