Bioactive-guided phytochemical investigation of
L. growing in Vietnam led to the isolation of five
-atisanes, one
-
-atisane, and one lathyrane (ingol-type). The structures were elucidated as
-1
3
16
...17-tetrahydroxyatisane (
), ethyl
-3,4-
-4,16
,17-trihydroxyatisane-3-carboxylate (
),
-atisane-3-oxo-16
,17-acetonide (
),
-3
-acetoxy-16
,17-dihydroxyatisane (
),
-16
,17-dihydroxyatisane-3-one (
), calliterpenone (
), and ingol 12-acetate (
). Their chemical structures were unambiguously determined by analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry, as well as by comparison with literature data. Among them,
is a new compound while
is an ethylated artifact of
-3,4-
-4,16
,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound
showed the most significant inhibitory activity against alpha-glucosidase with an IC
value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that
could retard the enzyme function by noncompetitive.
Kurz is widely used in folk medicine in Eastern Asia and is associated with various ethnopharmacological properties including hepatoprotective, antipyretic, analgesic, antidysenteric, and ...anthelmintic activities. Previous phytochemical investigations reported the presence of numerous triterpenes (mostly cycloartanes, ursanes, lupanes, and oleananes) along with dozens of flavonoids. However, the extracts of
and isolated flavonoids have not been evaluated for their alpha-glucosidase inhibition. In the frame of our efforts dedicated to the chemical investigation of Vietnamese medicinal plants and their biological activities, a phytochemical study of the MeOH extract of the leaves of
using bioactive guided isolation was undertaken. In this paper, the isolation and structure elucidation of twelve known compounds, 5-hydroxy-3,7,4'-trimethoxyflavone (
), ayanin (
), kumatakenin (
), rhamnocitrin (
), ombuin (
), myricetin-3,7,3',5'-tetramethyl ether (
), gardenin D (
), luteolin (
), apigenin (
), mearnsetin (
), isoorientin (
), and vitexin (
) were reported. Bromination was applied to compounds
and
to provide four new synthetic analogues
-
. All isolated and synthesized compounds were evaluated for alpha-glucosidase inhibition and antibacterial activity. Compounds
and
showed moderate antibacterial activity against methicillin-resistant
while others were inactive. All compounds failed to reveal any activity toward extended spectrum beta-lactamase-producing
. Compounds
,
,
-
, and
-
showed good alpha-glucosidase inhibition with IC
values in the range of 30.5-282.0 µM. The kinetic of enzyme inhibition showed that
and
were noncompetitive type inhibition against alpha-glucosidase. In silico molecular docking model indicated that compounds
and
were potential inhibitors against enzyme
-glucosidase.
A new natural Diels‐Alder adduct (3) was isolated from the leaves and stem bark of Artocarpus integer, along with seventeen known compounds (1, 2, and 4–18). Structural elucidation was conducted ...using NMR and HR‐ESI‐MS data, and comparisons were made with previous studies. Deoxyartonin I (3) exhibited the most potent α‐glucosidase inhibition (IC50 7.80±0.1 μM), outperforming the acarbose positive control. This was mixed‐mode inhibition, as indicated by the intersect in the second quadrant of each respective plot. An in silico molecular docking model and the pharmacokinetic features of 3 suggest that it is a potential inhibitor of enzyme α‐glucosidase, and is therefore a lead candidate as a drug against diabetes mellitus.
A novel oxime polyketide, maydisone (1), along with two known compounds, 7-hydroxy-2,5-dimethylchromone (2) and 2,5-dimethylbenzoic acid (3) were isolated from the cultures of Bipolaris maydis. Their ...structures were identified by the application of NMR and MS data analyses and comparison with previous reports. Compound 1 showed the most powerful inhibition of α-glucosidase, with an IC
50
value of 68.30 ± 0.83 µM.
Two new cycloartanes, combretic acid C (1) and combretanone I (3), were isolated from the leaves of Combretum quadrangulare Kurz, together with the previously-reported combretic acids A-B (2 and 5) ...and combretanone A (4). An extensive set of spectroscopic methods were used to elucidate the structures of these compounds. Cytotoxicity against the K562 cancer cell line was evaluated. Compound 1 showed strong activity, with an IC
50
value of 9.7 µM. The other compounds showed moderate activity. Alpha-glucosidase inhibition was also evaluated. The isolated compounds showed moderate inhibition, with IC
50
values in the range 102.2-194.7 µM.
Wild guava (Psidium guajava L.) commonly grows in tropical forests, and its leaves have long been used by Asian ethnic minorities as herbal tea and traditional medicine. This study aimed to evaluate ...the effects of different drying methods (sun drying, hot air drying, microwave drying, vacuum drying, and freeze drying) on the retention of bioactive compounds, antioxidant, and antidiabetic activities of wild guava leaves collected in Vietnam. The results showed that drying methods significantly affected the retention of bioactive compounds, biological activities, and color of guava leaves. The freeze-dried leaves had the highest levels of total phenolic content (173.25 ± 0.68 mg gallic acid equivalent g
−1
dw), total flavonoid content (24.46 ± 0.78 mg QE g
−1
dw), antioxidant capacity, and in vitro antidiabetic activity compared with others, while sun-dried leaves showed the lowest values of those parameters. The principal component analysis (PCA) showed a strong correlation among biological activities and contents of bioactive compounds, including antioxidant activity, in vitro antidiabetic activity, total phenolic content, and total flavonoid content (r
2
= 0.999, p < 0.0001). Specifically, the biological activities strongly and positively correlated epicatechin, rutin, chlorogenic acid, catechin, and gallic acid. Freeze-dried guava leaves had the highest positive scores, followed by hot air-dried, microwave-dried, vacuum-dried, and sun-dried samples. FD treatment sample also exhibited better color and sensory properties than others. Consequently, freeze drying is recommended as the most suitable drying method for preserving the bioactive compounds and sensory characteristics of dried wild guava leaves.
Adenosma bracteosum and Vitex negundo are natural sources of methoxylated flavonoids. Little is known about the α‐glucosidase inhibition of multi‐methoxylated flavonoid derivatives. Eighteen natural ...flavonoids were isolated from A. bracteosum and V. negundo. Seven halogenated derivatives were synthesized. Their chemical structures were elucidated by extensive NMR analysis and high‐resolution mass spectroscopy as well as comparisons in literature. All compounds were evaluated for their α‐glucosidase inhibition. Most compounds showed good activity with IC50 values ranging from 16.7 to 421.8 μM. 6,8‐Dibromocatechin was the most active compound with an IC50 value of 16.7 μM. A molecular docking study was conducted, indicating that those compounds are potent α‐glucosidase inhibitors.
A new depsidone, parmoferone A (1), together with three known compounds, parmosidone K (2), albifolione (3), and 4-chloroorcinol (4) were isolated from the lichen Parmotrema cristiferum (Taylor) Hale ...(Parmeliaceae). The structures of isolated compounds were identified from its spectroscopic data and by comparison with the literature. Compounds 1-4 were evaluated for alpha-glucosidase inhibition. Compound 1 was determined to be a potent non-competitive inhibitor against alpha-glucosidase with an IC
50
value of 18.1 μM.
Syzygium zeylanicum L. (DC) (SZL) has been used in antidiabetes treatment for ages. However, the scientific evidence of active agents that have antidiabetic activity and response against biological ...activities is limited. In this study, the active components of SZL trunk‐bark extract (SZL extract) were identified using principal component analysis (PCA), and their antidiabetic activities were assessed. The results indicated that the ethyl acetate fraction (EAF) had the highest concentration of phenolic compounds, antioxidants, and antihyperglycemic activities in the postprandial zebrafish model. The major antioxidant contributors were gallic acid, catechin, epicatechin, ellagic acid, quercetin, caffeine, and apigenin, and their concentrated levels reduced α‐amylase inhibitory activity, whereas rutin and ethyl gallate influenced the α‐glucosidase inhibitory activity. This study showed the bio‐functional properties of active phenolic compounds present in the SZL extract, potentially serving as a functional food to control hyperglycemia.
This study aims to investigate the primary bioactive component of Syzygium zeylanicum (L.) DC trunk‐bark during extraction and fractionation and assess their in vitro antioxidant and antidiabetes activity, the phenolic chemical profile, and their influence on the bioactivity of the extract and its fraction. Furthermore, the antihyperglycemic activity was evaluated on zebrafish model. The results showed the bio‐functional properties of active phenolic compounds present in the SZL extract and potentially serve as a functional food to control hyperglycemia.
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