Polyphenol Contents, Gas Chromatography-Mass Spectrometry (GC-MS) and Antibacterial Activity of Methanol Extract and Fractions of Sonneratia Caseolaris Fruits from Ben Tre Province in Vietnam.

Plants contain a large number of phytochemical components, many of which are known as bioactive compounds and responsible for the expression of various pharmacological activities. The extract of Sonneratia caseolaris fruit collected in Vietnam was investigated for its total phenolic and total flavonoid contents using methanol solvent and different fractions of S. caseolaris fruits (hexane, ethyl acetate, n-butanol, and aqueous). GC-MS analysis was conducted to identify the bioactive chemical constituents occurring in the active extract. Further, the antibacterial activity was tested in vitro on bacterial isolates, namely Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, using the disc diffusion method on tryptic soya agar (TSA) medium. The methanol extract showed high total flavonoid (82.3 ± 0.41 mg QE/g extract) and phenolic (41.0 ± 0.34 mg GAE/g extract) content. GC-MS of the methanol extract and different fractions of S. caseolaris fruits detected 20 compounds, principally fatty alcohols, fatty acids, phenols, lipids, terpenes derivatives, and carboxylic acids derivatives. A 50 mg/ml concentration of methanol extract had the strongest antibacterial activity on E. coli, S. aureus, and B. subtilis. Furthermore, ethyl acetate, aqueous, and n-butanol fractions inhibited S. aureus and B. subtilis the most. The results of the present study suggested that the fruits of S. caseolaris are rich sources of phenolic compounds that can contribute to safe and cost-effective treatments.

Antioxidant, α-Amylase and α-Glucosidase Inhibitory Activities and Potential Constituents of Canarium tramdenum Bark.

The fruits of Canarium tramdenum are commonly used as foods and cooking ingredients in Vietnam, Laos, and the southeast region of China, whilst the leaves are traditionally used for treating diarrhea and rheumatism. This study was conducted to investigate the potential use of this plant bark as antioxidants, and α-amylase and α-glucosidase inhibitors. Five different extracts of C. tramdenum bark (TDB) consisting of the extract (TDBS) and factional extracts hexane (TDBH), ethyl acetate (TDBE), butanol (TDBB), and water (TDBW) were evaluated. The TDBS extract contained the highest amount of total phenolic (112.14 mg gallic acid equivalent per g dry weight), while the TDBB extract had the most effective antioxidant capacity compared to other extracts. Its IC50 values were 12.33, 47.87, 33.25, and 103.74 µg/mL in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (ABTS), reducing power (RP), and nitric oxide (NO) assays, respectively. Meanwhile, the lipid peroxidation inhibition of the four above extracts was proximate to that of butylated hydroxytoluene (BHT) as a standard antioxidant. The result of porcine pancreatic α-amylase inhibition showed that TDB extracts have promising effects which are in line with the commercial diabetic inhibitor acarbose. Interestingly, the inhibitory ability on α-glucosidase of all the extracts was higher than that of acarbose. Among the extracts, the TDBB extract expressed the strongest activity on the enzymatic reaction (IC50 = 18.93 µg/mL) followed by the TDBW extract (IC50 = 25.27 µg/mL), TDBS (IC50 = 28.17 µg/mL), and TDBE extract (IC50 = 141.37 µg/mL). The phytochemical constituents of the TDB extract were identified by gas chromatography⁻mass spectrometry (GC-MS). The principal constituents included nine phenolics, eight terpenoids, two steroids, and five compounds belonging to other chemical classes, which were the first reported in this plant. Among them, the presence of α- and ß-amyrins were identified by GC-MS and appeared as the most dominant constituents in TDB extracts (1.52 mg/g). The results of this study revealed that C. tramdenum bark possessed rich phenolics and terpenoids, which might confer on reducing risks from diabetes. A high quantity of α- and ß-amyrins highlighted the potentials of anti-inflammatory, anti-ulcer, anti-hyperlipidemic, anti-tumor, and hepatoprotective properties of C. tramdenum bark.

Weed Suppressing Potential and Isolation of Potent Plant Growth Inhibitors from Castanea crenata Sieb. et Zucc.

This study isolated, determined, and quantified plant growth inhibitors in Japanese chestnut (Castanea crenata Sieb. et Zucc), a deciduous species native to Japan and Korea. In laboratory assays, C. crenata leaves showed strong inhibition on germination and seedling growth of Echinochloa crus-galli (barnyardgrass), Lactuca sativa (lettuce), and Raphanus sativus (radish). Laboratory and greenhouse trials showed that leaves of C. crenata appeared as a promising material to manage weeds, especially the dicot weeds. By GC-MS and HPLC analyses, gallic, protocatechuic, p-hydroxybenzoic, caffeic, ferulic, ellagic, and cinnamic acids were identified and quantified, of which ellagic acid was present in the highest quantity (2.36 mg/g dried leaves). By column chromatography and spectral data (¹H- and 13C-NMR, IR, and LC-MS) analysis, a compound identified as 2α,3ß,7ß,23-tetrahydroxyurs-12-ene-28-oic acid (1) was purified from the methanolic leaf extract of C. crenata (0.93 mg/g dried leaves). This constituent showed potent inhibition on growth of E. crus-galli, a problematic weed in agricultural practice. The inhibition of the compound 1 (IC50 = 2.62 and 0.41 mM) was >5 fold greater than that of p-hydroxybenzoic acid (IC50 = 15.33 and 2.11 mM) on shoot and root growth of E. crus-galli, respectively. Results suggest that the isolated the compound 1 has potential to develop natural herbicides to manage E. crus-galli. This study is the first to isolate and identify 2α,3ß,7ß,23-tetrahydroxyurs-12-ene-28-oic acid in a plant and report its plant growth inhibitory potential.

Potential Use of Plant Waste from the Moth Orchid (Phalaenopsis Sogo Yukidian "V3") as an Antioxidant Source.

This research was conducted to exploit the waste of used plant parts from the widely marketed moth orchid cultivar (Phalaenopsis Sogo Yukidian "V3"). Various extracts of roots, stems, and leaves were evaluated for total phenolics, total flavonoids, and antioxidant capacity. The bound extract from stems contained the highest total phenolics (5.092 ± 0.739 mg GAE (gallic acid equivalent)/g DW (dry weight)). The maximum total flavonoids (2.218 ± 0.021 mg RE (rutin equivalent)/g DW) were found in the hexane extract of leaves. Ethyl acetate extract from roots showed the greatest antioxidant activity compared to other extracts. Of these extracts, the IC50 values of these samples were 0.070 mg/mL, and 0.450 mg/mL in a free radical 1,-diphenyl-picryl-hydrazyl (DPPH) assay and reducing power method, respectively. The lipid peroxidation inhibition (LPI) was found to be 94.2% using the ß-carotene bleaching method. Five phenolic compounds including caffeic acid, syringic acid, vanillin, ellagic acid, and cinnamic acid were quantified by high performance liquid chromatography (HPLC). It is suggested that the roots of the hybrid Phalaenopsis Sogo Yukidian "V3" cultivar may be exploited as an effective source of antioxidants.

Phenolic Compositions and Antioxidant Properties in Bark, Flower, Inner Skin, Kernel and Leaf Extracts of Castanea crenata Sieb. et Zucc.

In this study, different plant parts (barks, flowers, inner skins, kernels and leaves) of Castanea crenata (Japanese chestnut) were analyzed for total phenolic, flavonoid, and tannin contents. Antioxidant properties were evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), reducing power, and ß-carotene bleaching methods. The highest total phenolic and tannin contents were found in the inner skins (1034 ± 7.21 mg gallic acid equivalent/g extract and 253.89 ± 5.59 mg catechin equivalent/g extract, respectively). The maximum total flavonoid content was observed in the flowers (147.41 ± 1.61 mg rutin equivalent/g extract). The inner skins showed the strongest antioxidant activities in all evaluated assays. Thirteen phenolic acids and eight flavonoids were detected and quantified for the first time. Major phenolic acids were gallic, ellagic, sinapic, and p-coumaric acids, while the principal flavonoids were myricetin and isoquercitrin. The inner skin extract was further fractionated by column chromatography to yield four fractions, of which fraction F3 exhibited the most remarkable DPPH scavenging capacity. These results suggest that C. crenata provides promising antioxidant capacities, and is a potential natural preservative agent in food and pharmaceutical industries.

Phenolic Compounds and Antioxidant Activity of Phalaenopsis Orchid Hybrids.

Phalaenopsis spp. is the most commercially and economically important orchid, but their plant parts are often left unused, which has caused environmental problems. To date, reports on phytochemical analyses were most available on endangered and medicinal orchids. The present study was conducted to determine the total phenolics, total flavonoids, and antioxidant activity of ethanol extracts prepared from leaves and roots of six commercial hybrid Phalaenopsis spp. Leaf extracts of "Chian Xen Queen" contained the highest total phenolics with a value of 11.52 ± 0.43 mg gallic acid equivalent per g dry weight and the highest total flavonoids (4.98 ± 0.27 mg rutin equivalent per g dry weight). The antioxidant activity of root extracts evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and ß-carotene bleaching method was higher than those of the leaf extracts. Eleven phenolic compounds were identified, namely, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, vanillin, ferulic acid, sinapic acid, p-coumaric acid, benzoic acid, and ellagic acid. Ferulic, p-coumaric and sinapic acids were concentrated largely in the roots. The results suggested that the root extracts from hybrid Phalaenopsis spp. could be a potential source of natural antioxidants. This study also helps to reduce the amount of this orchid waste in industrial production, as its roots can be exploited for pharmaceutical purposes.