Objective: α-Glucosidase inhibitors can be used as a new class of antidiabetic drug. By competitively inhibiting glycosidase activity, these inhibitors help to prevent the fast breakdown of sugars and thereby control the blood sugar level. This study provides a wealth of information about α-glucosidase inhibitors isolated from medicinal plants; this knowledge will be useful in finding more potent antidiabetic candidates from the natural resources for the clinical development of antidiabetic therapeutics. Results: 411 compounds exhibiting α-glucosidase inhibitory activity were summarized and isolated them from medicinal plants. The compound classes isolated include: terpenes (61) from 14 genus, alkaloids (37) from 11 genus, quinines (49) from 4 genus, flavonoids (103) from 24 genus, phenols (37) from 9 genus, phenylpropanoids (73) from 20 genus, sterides (8) from 5 genus, and other types of compounds (43). Conclusion: Compounds with α-glucosidase inhibitory activity are abundant in nature and can be obtained from several sources. They have high α-glucosidase inhibitory potential, and can be clinically developed for treating diabetes mellitus.

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BackgroundAntimicrobial resistance was one of serious worldwide problems confused many researchers. To solve this problem, we explored the antibacterial effect of chelerythrine, a natural compound from traditional Chinese medicine and studied its action.MethodsThe contents of chelerythrine from different fractions of Toddalia asiatica (Linn) Lam (T. asiatica) were determined. The anti-bacterial activities of chelerythrine were tested by disc diffusion method (K-B method). Scanning electron microscopy (SEM), alkaline phosphatase (AKP), bacterial extracellular protein leakage and SDS-PAGE analysis were also used to investigate the antibacterial mechanism of chelerythrine.ResultsAnalytic results of High Performance Liquid Chromatography showed that the content of chelerythrine (1.97 mg/g) in the ethyl acetate fraction was the highest, followed by those of methanol fraction and petroleum ether fraction. The in vitro anti-bacterial mechanisms of chelerythrine from T. asiatica were assessed. Chelerythrine showed strong antibacterial activities against Gram-positive bacteria, Staphylococcus aureus (SA), Methicillin-resistant S. aureus (MRSA), and extended spectrum β-lactamase S. aureus (ESBLs-SA). The minimum inhibitory concentrations (MICs) of chelerythrine on three bacteria were all 0.156 mg/mL. Furthermore, results suggested that the primary anti-bacterial mechanism of chelerythrine may be attributed to its destruction of the channels across the bacterial cell membranes, causing protein leakage to the outside of the cell, and to its inhibition on protein biosynthesis. Images of scanning electron microscope revealed severe morphological changes in chelerythrine-treated bacteria except control, damage of parts of the cell wall and cell membrane as well as the leakage of some substances.ConclusionsChelerythrine isolated from root of Toddalia asiatica (Linn) Lam possesses antibacterial activities through destruction of bacterial cell wall and cell membrance and inhibition of protein biosynthesis.

Plumbagin (PLB), a natural naphthoquinone constituent isolated from the roots of the medicinal plant Plumbago zeylanica L., exhibited anticancer activity against a variety of cancer cell lines including breast cancer, hepatoma, leukemia, melanoma, prostate cancer, brain tumor, tongue squamous cell carcinoma, esophageal cancer, oral squamous cell carcinoma, lung cancer, kidney adenocarcinoma, cholangiocarcinoma, gastric cancer, lymphocyte carcinoma, osteosarcoma, and canine cancer. PLB played anticancer activity via many molecular mechanisms, such as targeting apoptosis, autophagy pathway, cell cycle arrest, antiangiogenesis pathway, anti-invasion, and antimetastasis pathway. Among these signaling pathways, the key regulatory genes regulated by PLB were NF-kβ, STAT3, and AKT. PLB also acted as a potent inducer of reactive oxygen species (ROS), suppressor of cellular glutathione, and novel proteasome inhibitor, causing DNA double-strand break by oxidative DNA base damage. This review comprehensively summarizes the anticancer activity and mechanism of PLB.