Abelmoschus esculentus fractions potently inhibited the pathogenic targets associated with diabetic renal epithelial to mesenchymal transition

Abstract

Although Abelmoschus esculentus (AE) is known for anti-hyperglycemia, few reports have addressed its target. Our recent studies have focused on diabetic renal epithelial to mesenchymal transition (EMT), which plays a critical role in fibrosis that accompanies increasing vimentin and suggested signals DPP-4/AT-1/TGF-β1. This study aimed to investigate whether AE is useful for preventing diabetic renal EMT. We used a succession of extractions and obtained the corresponding fractions F1-F5, each with its own individual properties: F1 inhibits high glucose-stimulated vimentin, AT-1, TGF-β1, and DPP-4, and recovers E-cadherin in tubular cells; F2 decreases high glucose-induced vimentin, AT-1 and DPP-4; F3-F5 do not reduce the expression of vimentin. Chemical analysis revealed that F1 is rich of flavonoid glycosides especially quercetin glucosides, and pentacyclic triterpene ester. F2 contains a large amount of carbohydrates and polysaccharides composed of uronic acid, galactose, glucose, myo-inositol etc. In conclusion, AE has the potential to serve as an adjuvant for diabetic nephropathy, with F1 and F2 especially deserving further investigation and development.

Active subfractions of Abelmoschus esculentus substantially prevent free fatty acid-induced β cell apoptosis via inhibiting dipeptidyl peptidase-4

“…Monosaccharide and uronic analyses have revealed that F2 is enriched with uronic acid, galactose, glucose and myo-inositol, as well as rhamnose, fucose, and glucosamine [10]. Fucose-rich oligo- and polysaccharides can stimulate cell proliferation and promote cell survival, thus slowing the aging of skin fibroblasts [20].…”

“…The F1 and F2 subfractions of AE were prepared according to procedures shown in Fig 1. We previously reported LC-MS/MS analysis of F1, the alcohol-extracted fraction of AE [10]. F1 is comprised of at least 10 compounds, including quercetin glucosides (4.901 mg/g DW) and pentacyclic triterpene ester (4.301 mg/g DW) [S1 Table].…”

“…F1 is comprised of at least 10 compounds, including quercetin glucosides (4.901 mg/g DW) and pentacyclic triterpene ester (4.301 mg/g DW) [S1 Table]. The F2 subfraction of AE contains a large amount of carbohydrates and polysaccharides [10]. In addition, monosaccharide and uronic acid analyses revealed that F2 is rich in uronic acid (23.14%), galactose (18.92%), glucose (18.26%) and myo-inositol (14.21%), and also rhamnose, glucosamine, and fucose [S2 Table].…”

“…Following dissolution in isopropanol, the optical density was read at 563 nm with a spectrophotometer (Hitachi, U-3210) [10]. …”

“…Previously, we successfully isolated several subfractions (F1, F2, F3-F5, and FR) from AE using a series of successive extraction steps. Among these subfractions, F1 and F2 were found to be especially effective in suppressing the activity of DPP-4 [10]. This then successfully attenuated diabetic nephropathy, strongly suggesting that AE could serve as a promising adjuvant therapy for diabetes [10].…”