Human gait analysis plays an important role in musculoskeletal disorder diagnosis. Detecting anomalies in human walking, such as shuffling gait, stiff leg or unsteady gait, can be difficult if the ...prior knowledge of such a gait pattern is not available. We propose an approach for detecting abnormal human gait based on a normal gait model. Instead of employing the color image, silhouette, or spatio-temporal volume, our model is created based on human joint positions (skeleton) in time series. We decompose each sequence of normal gait images into gait cycles. Each human instant posture is represented by a feature vector which describes relationships between pairs of bone joints located in the lower body. Such vectors are then converted into codewords using a clustering technique. The normal human gait model is created based on multiple sequences of codewords corresponding to different gait cycles. In the detection stage, a gait cycle with normality likelihood below a threshold, which is determined automatically in the training step, is assumed as an anomaly. The experimental results on both marker-based mocap data and Kinect skeleton show that our method is very promising in distinguishing normal and abnormal gaits with an overall accuracy of 90.12%.
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.
Sphaeranthus africanus L. is native in Vietnam. Little is known about α‐glucosidase inhibition of Sphaeranthus africanus and its isolated compounds. A bioactive‐guided isolation was applied to the ...Vietnamese Sphaeranthus africanus to find α‐glucosidase inhibitory components. Eight compounds were detected and structurally elucidated. They are 3‐angeloyloxy‐5‐2′′,3′′‐epoxy‐2′′‐methylbutanoyloxy‐7‐hydroxycarvotacetone, 3‐angeloyloxy‐5‐3′′‐chloro‐2′′‐hydroxy‐2′′‐methylbutanoyloxy‐7‐hydroxycarvotacetone, 3‐angeloyloxy‐5‐2′′R,3′′R‐dihydroxy‐2′′‐methyl‐butanoyloxy‐7‐hydroxycarvotacetone, 3‐angeloyloxy‐5‐2′′S,3′′R‐dihydroxy‐2′′‐methylbutanoyloxy‐7‐hydroxycarvotacetone, 3‐angeloyloxy‐5‐2′′S,3′′S‐dihydroxy‐2′′‐methylbutanoyloxy‐7‐hydroxycarvotacetone, 5‐angeloyloxy‐7‐hydroxy‐3‐tigloyloxycarvotacetone, 3‐O‐methylquercetin, and chrysosplenol D. Their chemical structures were elucidated by extensive 1D and 2D NMR analysis and high‐resolution mass spectroscopy as well as comparisons in literature. 3‐Angeloyloxy‐5‐2′′S,3′′S‐dihydroxy‐2′′‐methylbutanoyloxy‐7‐hydroxycarvotacetone is a new compound. Isolated compounds were evaluated for the α‐glucosidase inhibition. Isolated compounds showed moderate activity with IC50 values ranging from 128.9–274.3 μM while others are weak. A molecular docking study was conducted, indicating that isolated compounds are potent α‐glucosidase inhibitory compounds.
Leaves of Combretum quadrangulare Kurz showed potent α‐glucosidase inhibition. Two new cycloartane‐type triterpenes, combretic acids D and E were isolated from the bioactive fraction. The chemical ...structures were determined using NMR and MS methods. Combretic acid D represents for the first cycloartane having a dihydrofuran ring in the side chain. Combretic acids D and E showed significant α‐glucosidase inhibition, with IC50 values of 13.9 and 30.7 μM, respectively. Combretic acid D was determined to be a non‐competitive type in the kinetic study. The docking study in combination with dynamic simulations of this compound provided the molecular understanding of α‐glucosidase inhibition.
Boerhavia erecta is a tropical plant that is widely used in Asian folk medicine. Little is known about the alpha-glucosidase inhibition and antimicrobial properties of compounds from this plant. In ...the present study, the phytochemical study of the aerial parts of B. erecta collected in Vietnam was conducted using multiple chromatographic methods. The chemical structures of isolated compounds were identified by comprehensive spectroscopic methods. Two new compounds, berectone C (1) and (E)-tetracosyl 3-(3-hydroxy-4-methoxyphenyl)acrylate (4), together with the known compounds boeravinone C (2), liquiritigenin (3), bis(1H-indol-3-yl)methanone (5), and indole-3-carboxylic acid (6) were isolated and structural elucidated. Compounds 1 and 4 were evaluated for alpha-glucosidase inhibition and antimicrobial activity against antibiotic-resistant, pathogenic bacteria Enterococcus faecium, Staphylococcus aureus, and Acinetobacter baumannii. Compound 1 showed strong inhibition of the alpha-glucosidase enzyme (IC
50
43 µg/mL). Only compound 1 exhibited antimicrobial property against A. baumannii, forming an inhibition zone of 11 mm.
Six new sulfonic acid-containing flavonoids, acidoflavanone (1), acidoauronol (2), 5- O-methylacidoauronol (3), acidoaurone (4), acidoisoflavone (5), and acidoflavonol (6), were isolated from the ...EtOH extract of the roots of Phyllanthus acidus. Their structures were unambiguously established by interpretation of their HRESIMS and 1D and 2D NMR data, single-crystal X-ray diffraction analysis, and comparison to the literature data. These new structures represent the first examples of sulfonic acid-containing flavanones, auronols, aurones, and isoflavones.
Lichen-derived depsidones have been a successful source for alpha-glucosidase inhibitory agents with numerous advantages. In this article, derivatives of protocetraric acids were designed and ...synthesised. Diels-Alder reaction, esterification, and Friedel-Crafts alkylation of protocetraric acid with different reagents under Lewis acid were performed. Eleven products were prepared, including 10 new compounds and parmosidone A. Among them, compounds 2-4 and 6 had the novel skeletons. The newly synthetic products were evaluated for alpha-glucosidase inhibition. Among tested compounds, 9 showed the strongest activity, with an IC
50
value of 5.9 µM. The molecular docking model indicated the consistency between in vitro and in silico data of alpha-glucosidase inhibition.
A new labdane-type diterpenoid, named vitexnegundin (1), along with seven known compounds, including vitexilactone (2), vitetrifolin D (3), 13-hydroxy-5(10),14-halimadien-6-one (4), (rel ...3S,5S,8R,9R,10S)-3,9-dihydroxy-13(14)-labden-16,15-olide (5), artemetin (6), vitexcarpin (7) and penduletin (8), were isolated from the leaves of Vitex negundo L. Their structures were elucidated by using spectroscopic methods, X-ray crystallographic analysis and comparison with those reported in the literature. Moreover, all isolated compounds 1-8 were evaluated for their antimicrobial activity against ESBL-producing Escherichia coli strain and methicillin-resistant Staphylococcus aureus.
Tecoma stans is a tropical plant that is widely used in folk medicine. Little is known about the chemical constituents of flowers of this plant. From flowers of the native plant in Vietnam, 12 ...compounds were isolated and elucidated, including one new compound tecomastane (1) and eleven known compounds, (3S,5R,6S,7E)-5,6-epoxy-3-hydroxy-7-megastigmane-9-one (2), bosciallin (3), chakyunglupulin B (4), (2S,6R)-2,6-dimethyloctane-1,8-diol (5), cleroindicin F (6), rengyoxide (7), 3,4-dihydroxybenzoic acid (8), methyl 3,4-dihydrobenzoate (9), 3,5-dihydroxybenzoic acid (10), luteolin (11), and indole-3-carboxylic acid (12). Compound 5 was a new natural product. The chemical structures of isolated compounds were identified by interpretation of their spectroscopic data (1D, 2D NMR, and HRESIMS) and by comparison with the literature. Compounds 1-7 and 10-12 were evaluated for alpha-glucosidase inhibition and antimicrobial activity against antibiotic-resistant, pathogenic bacteria Enterococcus faecium, Staphylococcus aureus, and Acinetobacter baumannii.
Boerhavia erecta is a tropical plant that is widely used in folk medicine. Roots of this plant are applied as a diuretic, stomachic, anthelminthic, febrifuge, and expectorant. The whole plant has ...been used for treating gastrointestinal, liver, and infertility problems. More than 40 metabolites have been identified in its leaves, roots, and the aerial parts. Among them, isoflavonoids such as rotenoids and coumaronochromonoids are major components. Some of these compounds exhibited potent cytotoxicity, COX inhibition and opioid and cannabinoid receptor. However, little is known about the inhibition of α-glucosidase enzyme of these compounds. As part of our ongoing search for α-glucosidase inhibitors from Vietnamese medicinal plants, we conducted bioactive-guided isolation of the aerial part of Boerhavia erecta. Twelve known compounds were isolated and elucidated, including boeravinone M (1), boeravinone G (2), boeravinone P (3), boeravinone B (4), boeravinone E (5), boeravinone A (6), boeravinone H (7), 9-O-methyl-4-hydroxyboeravinone B (8), boeravinone T (9), boeravinone J (10), boeravinone C (11), and 10-demethylboeravinone C (12). Isolates 2–5, 7, and 12 showed potent α-glucosidase inhibition, which is stronger than acarbose, a positive control. Among them, compound 5 showed strongest inhibition with IC50 value of 85.1 µM. A kinetic study indicated that 5 was a mixed-type inhibitor. Compound 5 was determined to be a potential inhibitor of the α-glucosidase enzyme based on in silico molecular docking mode. Compounds were tested for cytotoxicity against K562 and antimicrobial activity against antibiotic-resistant, pathogenic bacteria Enterococcus faecium, Staphylococcus aureus, and Acinetobacter baumannii. Only compounds 4 and 12 showed moderate activity against K562 cell line. As regards antimicrobial activity, compounds 6 and 10 showed strong inhibition toward Enterococcus faecium. In silico studies of cytotoxicity and antimicrobial activity were also performed, indicating that in vitro and in silico data were consistent.
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