Labisia pumila Upregulates Peroxisome Proliferator-Activated Receptor Gamma Expression in Rat Adipose Tissues and 3T3-L1 Adipocytes

Protective effects of Labisia pumila against neuropathy in a diabetic rat model

Purpose

Diabetes accelerates peripheral, distal symmetric polyneuropathy, small fiber predominant neuropathy, radiculoplexopathy, and autonomic neuropathy. This study investigated the neuroprotective effects of gallic acid and myricetin-rich Labisia pumila extract in a diabetic neuropathy rat model and evaluated the neuropathy correlationship with serum inflammatory biomarkers.

Methods

Thirty male rats were divided into 5 groups (n = 6), namely: healthy control; non-treated diabetic control; and diabetic-rats treated with 200 mg/kg metformin; Labisia pumila ethanol extract (LP) at 150 mg/kg or 300 mg/kg doses. Diabetes was induced by 60 mg streptozotocin /kg intraperitoneal injection. Rats were orally treated daily for ten weeks. Their fasting blood glucose (FBG), neurological functions (hot plate and tail immersion; thermal hyperalgesia; cold allodynia; motor walking function), biomarkers for inflammation and oxidative stress, the neuro-histopathological changes, and brain somatic index were measured.

Results

The extract significantly prevented abnormal increases in FBG and decreases in body weight gain. It attenuated behavioral dysfunctions (hot plate and tail immersion; thermal hyperalgesia; cold allodynia; motor walking function), systemic inflammation (serum TNF-α, prostaglandin-E2) oxidative tension (malondialdehyde), histological brain and sciatic nerve injuries in the diabetic-rats, better than Metformin.

Conclusion

LP mitigated neural dysfunction better than metformin partly by amending diabetic systemic inflammation, oxidative tension, and diabetic abnormalities. The nerve injuries were strongly correlated to serum prostaglandin-E2, TNF-α levels, and walking functions. The motor function was correlated to sensory neuronal functions, inflammation, and oxidation. The sensory neuronal functions were more affected by TNF-α than prostaglandin-E2 or oxidation. Diabetic brain and sciatic nerve deteriorations were influenced by serum TNF-α, PGE2, and MDA levels.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00905-0.

Gallic acid and myricetin-rich Labisia pumila extract mitigated multiple diabetic eye disorders in rats

Diabetes affected about a quarter of a billion people globally, and one out of four diabetics has eye or vision problems. This study investigated whether gallic acid and myricetin-rich Labisia pumila extract (LP) consumption would help prevent diabetic eye disorders and some probable biochemistry involved relating to inflammation, vascular leakage, and oxidative tension. Male rats were divided into four groups (n = 6), namely healthy control, diabetic non-treated control, and hyperglycemic rats treated with 150 or 300 mg/kg LP. Intraperitoneal injection of 60 mg/kg streptozotocin was used to induce diabetes. Rats were fed in the morning and evening. Diabetic retinopathy was graded in rats using a dilated retinal digital ophthalmoscopy. Rats were sacrificed at 12 weeks and the retina, optic nerve, cornea, lens, sclera, ciliary bodies, iris, and conjunctiva were examined histologically. The diabetic rats consuming LP for 10 weeks showed dose-dependent, histopathologically-reduced eye abnormalities (keratopathy, cataract, sclera, conjunctiva, ciliary bodies, iris, limbus, corneal edema, epithelial barrier inefficiency, shallow punctate keratitis, lower basal layer cell density, retinopathy, glaucoma, and corneal changes). The LP significantly suppressed inflammation [increased serum tumor necrosis factor-α (TNF-α), prostaglandin-E2 (PGE2)], vascular leakage [claudin-1], abnormal vascularization [vascular endothelial growth factor (VEGF)], oxidative tension [malondialdehyde/reduced glutathione ratio], and hyperglycemia [fasting blood glucose] of the diabetic rats. The LP consumption was significantly protective against diabetic eye disorders and optic nerve dysfunction which were related to inflammation, vascular leakage, abnormal vascularization, and oxidative tension, which most likely influenced eye hemorrhage and collagen cross-linkage. PRACTICAL APPLICATIONS: The study shows that gallic acid and myricetin-rich Labisia pumila (LP) leaf consumption may be used as a complementary therapy for managing diabetes (fasting blood glucose) and preventing diabetic eye disorders (keratopathy, cataract, sclera, conjunctiva, ciliary bodies, iris, limbus, corneal edema, epithelial barrier inefficiency, shallow punctate keratitis, lower basal layer cell density, retinopathy, glaucoma, and corneal abnormalities). The LP consumptions reduced the serum biomarkers for inflammation (serum tumor necrosis factor-α TNF-α; prostaglandin-E2), vascular leakage/abnormalities (claudin-1 and vascular endothelial growth factor VEGF), and oxidative tension (malondialdehyde/reduced glutathione MDA/GSH ratio). The LP was eye-protective probably by normalizing fasting blood glucose, reducing inflammation, oxidative tension, vascular leakage, and irregular vascularization.

DNA Microarray Analysis of Estrogen Responsive Genes in Ishikawa Cells by Glabridin

Based on a previous study, glabridin displayed a dose-dependent increase in estrogenic activity and cell proliferative activity in Ishikawa cells. However, when treated in combination with 17β-E₂, synergistic estrogenic effect was observed but without the same synergistic increase in cell proliferative effect. This study aimed to identify the estrogen and nonestrogen-regulated activities induced by glabridin and in combination with 17β-E₂ in comparison with 17β-E₂. The results showed that 10 µM glabridin and the combination treatment of 100 nM glabridin with 1 nM 17β-E₂ regulated both the genomic and nongenomic estrogen pathways to possibly provide benefits of estrogens in cardiovascular, circulatory, and vasculature systems. Meanwhile, the combination of 100 nM glabridin with 1 nM 17β-E₂ seems to be more suitable to be used as an estrogen replacement. Finally, the results of this study have added on to the present knowledge of glabridin’s function as a phytoestrogen and suggested new ideas for the usage of glabridin.

[Beneficial effect of periodontal therapy on insulin resistance and lipid metabolism in obese rats with periodontitis]

OBJECTIVE

To investigate the effect of periodontal therapy in controlling periodontitis and on insulin resistance and lipid metabolism in obese rats with periodontitis.

METHODS

Sprague-Dawley rats were randomized into normal group (group C), obese group (group O), periodontitis combined with obesity group (group P) and periodontal treatment group (group T). The obese rats in groups P and T were subjected to ligation of the maxillary second molar with silk thread to induce experimental periodontitis, and the rats in group T received periodontal therapy after the ligation. All the rats were sacrificed at the age of 24 weeks for measurement of blood lipids, insulin and blood glucose levels, and insulin resistance index (HOMA-IR) was calculated. The expressions of insulin receptor substrate-1 (IRS-1) and IRS-2 in the liver tissues were detected using real-time quantitative polymerase chain reaction (RT-PCR).

RESULTS

Compared with the obese rats in group O, the rats in group P showed significantly higher HOMA-IR and LDL-C and lower expressions of IRS-1 and IRS-2 mRNA expression and HDL-C level (P<0.05). Compared with those in group P, the mRNA expressions of IRS-1 and IRS-2 and HDL-C level were significantly increased and LDL-C level, TC level and HOMA-IR were all decreased in group T (P<0.05), but the level of TG was comparable between the two groups. Pathological examination revealed lessened inflammatory cell infiltration and tissue destruction in the upper jaw of the rats in group T; the rats in group P presented with the most obvious upper jaw destruction and steatosis and inflammatory cell infiltration in the liver.

CONCLUSION

Periodontal inflammation can downregulate the expression of IRS-1 and IRS-2 and increase insulin resistance and dyslipidemia in obese rats. Periodontal therapy produces a beneficial effect in improving insulin resistance and reducing dyslipidemia in obese rats.

Nymphaea nouchali Burm. f. hydroalcoholic seed extract increases glucose consumption in 3T3-L1 adipocytes through activation of peroxisome proliferator-activated receptor gamma and insulin sensitization

Nymphaea nouchali Burm. f. (Family – Nymphaeaceae) is a well-known medicinal plant used in the Indian ayurvedic system of medicine for treating diabetes. The seeds especially have been prescribed for diabetes. The hydroalcoholic extract of N. nouchali seeds has been demonstrated to possess anti-hyperglycemic effects in diabetic rats, but the functional mechanism remains unknown. The nuclear receptor, peroxisome proliferator-activated receptor gamma (PPARγ) is noted to play an important role in glucose and lipid homeostasis. This study was hence focused in evaluating the effect of the extract on PPARγ activation, adipocyte differentiation, and glucose consumption in 3T3-L1 cells. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), followed by adipogenesis assay using Oil Red O technique. Glucose consumption of preadipocytes and adipocytes in the presence of the extract was also determined. Real-time polymerase chain reaction was performed to identify the expression of genes involved in glucose consumption in the adipocytes. MTT assay confirmed the extract to be nontoxic, and Oil Red O staining confirmed enhanced adipocyte differentiation of 3T3-L1 cells in a dose-dependent manner. The extract also increased the expression of PPARγ target gene, which in turn enhanced the expression of GLUT-4. The data, therefore, suggests that N. nouchali seed extract promotes adipocyte differentiation and glucose consumption by inducing PPARγ activation, which in turn increases mRNA GLUT-4 expression and subsequently enhances insulin-responsiveness in insulin target tissues.