Analysis and comparison of the active components and antioxidant activities of extracts from Abelmoschus esculentus L

Abstract

Background:Abelmoschus esculentus L. is a healthy vegetable belonging to the family Malvaceae. This article reports the contents of total phenolics (TP) and total flavonoids (TF) in 80% methanol extracts of the flower (FL), fruit (FR), leaf (L), and seed (S) of A. esculentus, and in 0, 10, 30, 50, and 70% methanol eluates (ME), through the HP-20 column chromatography of 80% of the methanol fruit extract after it is defatted with petroleum and extracted with ethyl acetate. All the names of the samples are shortened for AEE-FL, AEE-FR, AEE-L, AEE-S and 0% MEF-WE, 10% MEF-WE, 30% MEF-WE, 50% MEF-WE, 70% MEF-WE respectively. In addition, the effects of the aforementioned extracts on 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging and on ferric reducing antioxidant power (FRAP) have been evaluated.Materials and Methods:The antioxidant activity of the extracts and the enrichment fraction of A. esculentus were also evaluated by two assays, the DPPH radical-scavenging and ferric reducing antioxidant power (FRAP). The content measurement of TF and TP adopts the UV-2102 PCS method, and the measurement of the antioxidant activity adopts the Infinite M 200 method.Results:The experiment results show that all the different parts and different enrichment fractions of the water extracts of A. esculentus contain phenolics and flavonoids. Through the research of antioxidant activity we know that all the parts of the methanol extracts and different enrichment fractions of water extracts in the A. esculentus have the effect of scavenging free radicals, among which the antioxidant activity in the 50% MEF-WE part is the strongest. Here, the main components of antioxidant activity must be the flavonoids and phenolics, and furthermore, we know that there is a direct relationship between the contents of flavonoids and phenolics and the antioxidant activity.Conclusion:The study suggests that A. esculentus may be the potential rich source of natural antioxidant. The experiment result provided a scientific basis for the further research and development of A. esculentus.

Phenolic Compounds, Antioxidant Activities, and Inhibitory Effects on Digestive Enzymes of Different Cultivars of Okra (Abelmoschus esculentus)

“…Results showed that the antioxidant capacities ranged from 13.28 µmol TE/g DW ("Royal red") to 22.87 µmol TE/g DW ("Shuiguo") in DPPH assay, from 90.65 µmol TE/g DW ("Royal red") to 173.99 µmol TE/g DW ("Shuiguo") in ABTS assay, and from 56.92 µmol TE/g DW ("Royal red") to 211.36 µmol TE/g DW ("Shuiguo") in FRAP assay. Results were similar to previous studies [4,5]. All the tested okra fruits showed significant antioxidant capacities, but varied by different cultivars, of which "Shuiguo" showed the highest, followed by "Kalong 8", "Kalong 3", and "Wufu", while "Royal red" showed the lowest, regardless of assay method.…”

“…Phenolic compounds are considered as one of the major bioactive components in okra fruits [2,5]. Therefore, phenolic compounds in different cultivars of okra fruits cultivated in China were investigated.…”

“…It is commonly considered that okra fruits can prevent diabetes and obesity [2,4]. In addition, it is also believed that okra fruits possess various bioactivities, such as anti-hyperlipidemic [1], antioxidant [5,6], anti-hyperglycemic [7], and neuroprotective activities [8]. Generally, polysaccharides and phenolic compounds are referred to the major bioactive components in okra fruits, which are also the sources of its various biological activities [9].…”

Antioxidant and Anti-Fatigue Constituents of Okra

“…The TP content was determined using Folin–Ciocaiteu method with slight modification [ 38 ]. In short, 50 mg sample was mixed with 25 mL of 50% methanol solution, then 0.5 mL sample solution, 0.3 mL Folin–Ciocaiteu’s reagent and 10 mL sodium carbonate (10%) were sufficiently mixed, and then the volume was adjusted to 25 mL with distilled water.…”

Antifatigue effects of ethanol extracts and polysaccharides isolated from Abelmoschus esculentus

“…Through literature retrieval, A. esculentus is rich in functional constituents such as flavonoids,[ 5 ] polysaccharides, pectin of fruit, trace elements, and amino acid. It also has the medical effects of antifatigue, antiageing, immune strengthening, liver protecting, blood sugar reducing, eyesight improving, internal fever removing, digestion helping, stomach invigorating, intestine lubricating, kidney strengthening, blood lipid reducing, etc.…”