Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
BMC Biotechnol. 2020 Oct 2;20(1):52. doi: 10.1186/s12896-020-00644-9.
Obesity and its related diseases are increasing worldwide. One of the best therapeutic strategies for obesity management is through the inhibition of pancreatic lipase (PL) enzyme. So far orlistat is the only FDA approved PL inhibitor, but with unpleasant side effects. New efficacious anti-obesity drugs are needed to achieve a successful reduction in the incidence and prevalence of obesity. Many microbial metabolites have PL inhibitory activity. Screening soil inhabitants for PL inhibitors could help in increasing the available anti-obesity drugs. We aimed to isolate and identify alternative PL inhibitors from soil flora.
We screened the crude mycelial methanolic extracts of 39 soil samples for PL inhibitory activity by the quantitative lipase colorimetric assay, using the substrate p-nitrophenyl palmitate and orlistat as positive control. AspsarO, a PL inhibitor producer, was isolated from an agricultural field soil in Giza, Egypt. It was identified as Aspergillus oryzae using colony morphology, microscopical characteristics, 18S rDNA sequencing, and molecular phylogeny. Increasing the PL inhibitor activity, in AspsarO cultures, from 25.9 ± 2% to 61.4 ± 1.8% was achieved by optimizing the fermentation process using a Placket-Burman design. The dried 100% methanolic fraction of the AspsarO culture had an IC of 7.48 μg/ml compared to 3.72 μg/ml for orlistat. It decreased the percent weight gain, significantly reduced the food intake and serum triglycerides levels in high-fat diet-fed Sprague-Dawley rats. Kojic acid, the active metabolite, was identified using several biological guided chromatographic and H and C NMR techniques and had an IC of 6.62 μg/ml. Docking pattern attributed this effect to the interaction of kojic acid with the key amino acids (Lys80, Trp252, and Asn84) in PL enzyme binding site.
Combining the results of the induced obesity animal model, in silico molecular docking and the lipase inhibitory assay, suggests that kojic acid can be a new therapeutic option for obesity management. Besides, it can lower serum triglycerides in obese patients.
肥胖及其相关疾病在全球范围内呈上升趋势。肥胖管理的最佳治疗策略之一是抑制胰腺脂肪酶（PL）。到目前为止，奥利司他是唯一获得 FDA 批准的 PL 抑制剂，但会产生令人不快的副作用。需要新的有效的抗肥胖药物来成功降低肥胖的发病率和流行率。许多微生物代谢物具有 PL 抑制活性。从土壤生物中筛选 PL 抑制剂有助于增加可用的抗肥胖药物。我们旨在从土壤菌群中分离和鉴定替代 PL 抑制剂。
我们通过使用定量脂肪酶比色法，用底物对硝基苯棕榈酸酯和奥利司他作为阳性对照，筛选了 39 个土壤样本的粗菌丝甲醇提取物，以评估其 PL 抑制活性。从埃及吉萨的农田土壤中分离出一种 PL 抑制剂产生菌 AspsarO。通过菌落形态、显微镜特征、18S rDNA 测序和分子系统发育，将其鉴定为米曲霉。通过使用 Placket-Burman 设计优化发酵工艺，将 AspsarO 培养物中的 PL 抑制剂活性从 25.9±2%提高到 61.4±1.8%。AspsarO 培养物的 100%甲醇干燥部分的 IC 为 7.48μg/ml，而奥利司他的 IC 为 3.72μg/ml。它降低了高脂肪饮食喂养的 Sprague-Dawley 大鼠的体重增加百分比，显著减少了食物摄入量和血清甘油三酯水平。通过几种生物导向的色谱和 H 和 C NMR 技术鉴定出活性代谢物——曲酸，其 IC 为 6.62μg/ml。对接模式将这种作用归因于曲酸与 PL 酶结合位点关键氨基酸（Lys80、Trp252 和 Asn84）的相互作用。
结合肥胖诱导动物模型的结果、计算机分子对接和脂肪酶抑制试验，表明曲酸可能成为肥胖管理的新治疗选择。此外，它可以降低肥胖患者的血清甘油三酯水平。
