Pressurized Hot Water Extraction of Okra Seeds Reveals Antioxidant, Antidiabetic and Vasoprotective Activities

Abstract

Abelmoschus esculentus L. Moench (okra) is a commonly consumed vegetable that consists of the seeds and peel component which are rich in polyphenolic compounds. The aim of this study is to utilize pressurized hot water extraction (PHWE) for the extraction of bioactive phytochemicals from different parts of okra. A single step PHWE was performed at various temperatures (60 °C, 80 °C, 100 °C and 120 °C) to determine which extraction temperature exhibits the optimum phytochemical profile, antioxidant and antidiabetic activities. The optimum temperature for PHWE extraction was determined at 80 °C and the biological activities of the different parts of okra (Inner Skin, Outer Skin and Seeds) were characterized using antioxidant (DPPH and ABTS), α-glucosidase and vasoprotective assays. Using PHWE, the different parts of okra displayed distinct phytochemical profiles, which consist of primarily polyphenolic compounds. The okra Seeds were shown to have the most antioxidant capacity and antidiabetic effects compared to other okra parts, likely to be attributed to their higher levels of polyphenolic compounds. Similarly, okra Seeds also reduced vascular inflammation by downregulating TNFα-stimulated VCAM-1 and SELE expression. Furthermore, metabolite profiling by LC/MS also provided evidence of the cytoprotective effect of okra Seeds in endothelial cells. Therefore, the use of PHWE may be an alternative approach for the environmentally friendly extraction and evaluation of plant extracts for functional food applications.

Valorization of avocado seeds with antioxidant capacity using pressurized hot water extraction

“…4 b). The current data was consistent with our earlier work where distinctive clusters were observed after the cells were treated with H 2 O 2 28 . Based on the VIP values in Fig.…”

“…LC/UV/MS was used to determine the phytochemical characteristic profile in different avocado seed extracts as previously described 11 , 28 . A C18 reverse phase High Performance Liquid Chromatography (HPLC) column (Zorbax SB-C18-3.5 microns, 4.6 × 100 mm) was used for compound separation.…”

Immunomodulatory effects of Abelmoschus esculentus water extract through MAPK and NF-κB signaling in RAW 264.7 cells

“…Despite previous studies demonstrating that A. esculentus has anti-inflammatory, anti-diabetic, anti-tumor, anti-bacterial, and anti-oxidant activities, its immune-stimulatory activity has not thus far been studied. 12 , 13 , 14 , 15 This is the first study to describe the immune-stimulatory activity of A. esculentus water extract in RAW264.7 macrophages. Macrophages are important components of the host defense system, and are involved at all stages of the immune response.…”

“…Owing to these effects, okra has also been referred to as “green ginseng”. 12 , 13 , 14 , 15 According to reports on its nutritional composition and phytochemical structure, A. esculentus contains a number of antioxidant vitamins (e.g., folate, niacin, choline, A, K, E, and β-carotene) as well as lipids, minerals, carbohydrates, dietary fibers, and amino acids. Moreover, it also contains health-promoting phenolics and flavonoids such as epigallocatechin, myricetin, gossypetin-8-O-β-D-glucuronide, quercetin glycosides and other quercetin derivatives and its glycosides, and gossypetin-8-O-β-D-glucuronide.…”

Roles of Reactive Oxygen Species in Vascular Complications of Diabetes: Therapeutic Properties of Medicinal Plants and Food

“…Okra (Malvaceae) shows antidiabetic properties that include anti-oxidation, antiinflammatory, and blood glucose and lipid regulation [193,194]. Okra seed extract reduced TNFα-stimulated VCAM-1 and SELE expression and protected HMEC-1 from H 2 O 2 injury, which might be attributed to high concentrations of quercetin 3-O-(malonyl)-glucose, quercetin Cortex-3-O-glucose-xylose and kaempferol-3-O-glucose [195]. In LDLr-KO mice, okra alleviated atherosclerotic lesion development of the aorta [196].…”