Department of Studies in Botany, University of Mysore, Mysore, Karnataka, India.
Lett Appl Microbiol. 2014 May;58(5):433-9. doi: 10.1111/lam.12209. Epub 2014 Jan 9.
α-amylase inhibitor retards the liberation of glucose from dietary complex carbohydrates and delays the absorption of glucose. The purpose of the study was to isolate and select α-amylase inhibitor-producing endophytic actinomycetes from the leaves and stems of Leucas ciliata and Rauwolfia densiflora, two of the well-known medicinal plants used in the treatment for diabetes. Sterilized plant samples were inoculated on the actinomycete isolation agar medium containing 50 ppm cycloheximide and incubated for 4-8 weeks at room temperature. The actinomycetes were isolated on agar medium and identified on the basis of 16S rRNA sequences, the isolates exhibiting >99% similarities were submitted to NCBI, and gene accession numbers were obtained. They were inoculated to International Streptomyces Project 1 medium (ISP 1) for fermentation. The extracts obtained were tested for the anti-diabetic potential by the inhibition of alpha-amylase by colorimetric assay and glucose uptake in the porcine hemidiaphragm. Streptomyces longisporoflavus (JX965948) isolated from the stem fragments of L. ciliata exhibited alpha-amylase inhibitory activity (IC50 values = 162.3 ± 1.05 μg ml⁻¹) in comparison with the standard Acarbose™ (IC50 value = 73.1 ± 1.12 μg ml⁻¹). Extract of Streptomyces sp. (JQ926174) from R. densiflora indicated glucose uptake in the porcine hemidiaphragm. Results indicate for the first time the potential of endophytic streptomycete extracts with anti-diabetic activity.
Endophytic actinomycetes were isolated from two medicinal species of the Western Ghats, a biodiversity 'hotspot' in southern India and screened for the anti-diabetic potential for inhibition of α-amylase and improved glucose uptake in the porcine hemidiaphragm. Results indicate the inhibition of α-amylase by Streptomyces longisporoflavus extract with IC50 values of 162.3 ± 1.05 μg ml⁻¹ in comparison with the standard inhibitor Acarbose™ with IC50 value 73.1 ± 1.12 μg ml⁻¹. Further, extract from Streptomyces sp. showed increased glucose uptake by hemidiaphragm. The present investigation implicates the potential of endophytic actinomycetes as sources of anti-diabetic agents.
α-淀粉酶抑制剂可延缓膳食复合碳水化合物中葡萄糖的释放，并延迟葡萄糖的吸收。本研究的目的是从两种常用于治疗糖尿病的著名药用植物——Leucas ciliata 和 Rauwolfia densiflora 的叶片和茎部分离和筛选产α-淀粉酶抑制剂的内生放线菌。将灭菌的植物样品接种到含有 50ppm 环己酰亚胺的放线菌分离琼脂培养基上，在室温下培养 4-8 周。将放线菌在琼脂培养基上分离，并根据 16S rRNA 序列进行鉴定，相似度>99%的分离株被提交给 NCBI，并获得基因访问号。将它们接种到国际链霉菌项目 1 培养基（ISP 1）中进行发酵。通过比色法测定α-淀粉酶抑制作用和猪膈肌中葡萄糖摄取来检测提取物的抗糖尿病潜力。从 Leucas ciliata 茎段中分离出的长孢链霉菌（JX965948）表现出α-淀粉酶抑制活性（IC50 值= 162.3 ± 1.05μgml⁻¹），与标准阿卡波糖（IC50 值= 73.1 ± 1.12μgml⁻¹）相比。从 Rauwolfia densiflora 中分离出的链霉菌（JQ926174）提取物在猪膈肌中显示出葡萄糖摄取。结果首次表明具有抗糖尿病活性的内生链霉菌提取物具有潜力。
从印度南部生物多样性热点——西高止山脉的两种药用物种中分离出内生放线菌，并筛选其抑制α-淀粉酶和改善猪膈肌中葡萄糖摄取的抗糖尿病潜力。结果表明，长孢链霉菌提取物对α-淀粉酶的抑制作用，IC50 值为 162.3 ± 1.05μgml⁻¹，与标准抑制剂阿卡波糖的 IC50 值 73.1 ± 1.12μgml⁻¹相比。此外，链霉菌提取物可增加膈肌对葡萄糖的摄取。本研究表明，内生放线菌具有作为抗糖尿病药物来源的潜力。
