@inpc.ac.vn
Department of Bioactive Products
Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology
Phytochemistry (isolation and structural elucidation of natural compounds), semisynthesis of natural compounds, pharmaceutical and medicinal chemistry
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Nguyen Manh Cuong, Pham Ngoc Khanh, Tran Thu Huong, Nguyen Xuan Ha, Hoang Thi Ngoc Anh, Vu Thanh Loc, Do Huu Nghi, Do Thi Thao, Trinh Thi Thu Ha, Nguyen Phi Hung,et al.
Publishing House for Science and Technology, Vietnam Academy of Science and Technology (Publications)
Rhubarb roots (Rheum officinale), a common medicinal plant in folk remedies, and their chemical compositions were investigated for their inhibitory activity of angiotensin-converting enzyme II and anti-inflammatory effects by inhibiting NO production and IL-6 expression. Four natural compounds, including two anthraquinones, chrysophanol (2) and emodin (3), and two stilbenes, rhapontigenin (1) and trans-piceatannol (4), were isolated from the roots of Rhubarb. The results showed that rhapontigenin (1) exhibited an inhibitory effect on the ACE-2 enzyme with an IC50 value of 132 mM. In an in silico study, rhapotigenin (1) had a binding energy value of -9.32 kcal/mol, lower than MLN-4760, on ACE-2. Both rhapontigenin (1) and emodin (3) exhibited inhibitory activity on NO production in primary cultures of macrophages RAW264.7, with IC50 values ranging from 5.65 to 32.3 µg/mL. This is the first study of the anti-ACE-2 and anti-inflammatory activity of Rhubarb root extract and its constituents.
Nguyen Xuan Ha, Tran Thu Huong, Pham Ngoc Khanh, Nguyen Phi Hung, Vu Thanh Loc, Vu Thi Ha, Dang Thu Quynh, Do Huu Nghi, Pham The Hai, Christopher J. Scarlett,et al.
Pharmaceutical Society of Japan
In Vietnam, the stems and roots of the Rutaceous plant Paramignya trimera (Oliv.) Burkill (known locally as "Xáo tam phân") are widely used to treat liver diseases such as viral hepatitis and acute and chronic cirrhosis. In an effort to search for Vietnamese natural compounds capable of inhibiting coronavirus based on molecular docking screening, two new dimeric coumarin glycosides, namely cis-paratrimerin B (1) and cis-paratrimerin A (2), and two previously identified coumarins, the trans-isomers paratrimerin B (3) and paratrimerin A (4), were isolated from the roots of P. trimera and tested for their anti-ACE-2 inhibitory properties in vitro. It was discovered that ACE-2 enzyme was inhibited by cis-paratrimerin B (1), cis-paratrimerin A (2), and trans-paratrimerin B (3), with IC50 values of 28.9, 68, and 77 μM, respectively. Docking simulations revealed that four biscoumarin glycosides had good binding energies (∆G values ranging from -10.6 to -14.7 kcal/mol) and mostly bound to the S1' subsite of the ACE-2 protein. The key interactions of these natural ligands include metal chelation with zinc ions and multiple H-bonds with Ser128, Glu145, His345, Lys363, Thr371, Glu406, and Tyr803. Our findings demonstrated that biscoumarin glycosides from P. trimera roots occur naturally in both cis- and trans- diastereomeric forms. The biscoumarin glycosides Lys363, Thr371, Glu406, and Tyr803. Our findings demonstrated that biscoumarin glycosides from P. trimera roots hold potential for further studies as natural ACE-2 inhibitors for preventing SARS-CoV-2 infection.
Nguyen Manh Cuong, Pham Ngoc Khanh, Le Thi Hong Nhung, Nguyen Xuan Ha, Tran Thu Huong, Katarina Bauerova, Young Ho Kim, Do Dinh Tung, Trinh Thi Thuy, and Nguyen Thi Hoang Anh
Informa UK Limited
From the root bark of Pinus krempfii Lecomte, four flavonoids were isolated and evaluated for their inhibitory activities against AChE and BChE enzymes in vitro and in silico. Tectochrysin (1) was found to inhibit AChE with an IC50 value of 33.69 ± 2.80 μM. The docking study results also showed agreement with the in vitro test results. All four compounds also showed the best binding affinity for the AChE enzyme, characterised by binding energy (ΔG) values as low as -8.1 to -9.3 kcal/mol, in which, the compound tectochrysin had the best binding affinity for the AChE protein with a ΔG value of -9.329 kcal/mol. Tectochrysin (1) was also bound to the amino acid Phe295 of AChE with a bond length of 2.8 Å, similar to the control dihydrotanshinone-I. Galangin (2) also showed its in vitro inhibitory activity against BChE with an IC50 value of 82.21 ± 2.70 μM. In silico, it also had the best binding energy value of -9.072 kcal/mol with BChE and formed hydrogen bonds with the His438 (2.85 Å) residues of BChE like the positive control (tacrine). The steered molecular dynamics (SMD) simulation results of these two complexes revealed a mechanistic insight that the protein-ligand complexes showed stable trajectories throughout the 20 and 150 ns simulations. Moreover, the drug likeliness suggested that both flavonoids (1 and 2) were expected to be drug-like and have an LD50 toxicity level of 5. This study has contributed new results for drug discovery and the development of substances with neuroprotective effects, especially for the treatment of Alzheimer's disease.Communicated by Ramaswamy H. Sarma.
Nadjet Mostefa, Noureddine Djebli, Pham Ngoc Khanh, Nguyen Xuan Ha, Hoang Thi Ngoc Anh, Vu Thi Ha, Tran Thu Huong, Dang Viet Anh, and Nguyen Manh Cuong
Wiley
The stilbene-rich acetone fraction in high yield (6.6%, PEAS) of Passiflora edulis Sims was prepared and evaluated for neuroprotective activity in murine Alzheimer's disease model induced by aluminum chloride and D-galactose. The phytochemical and HPLC-DAD-MS analysis of the polyphenolic stilbene-rich acetone fraction showed that it contained different stilbenes including trans-piceatannol, scirpusins A-B and cassigarol E. The total phenolic content (TPC) of PEAS was 413.87 ± 1.71 mg GAE eqv/g. The neuroprotective activity of PEAS is typically presented in the Morris water maze-reference Spatial Memory test, where the Alzheimer's mice treated at 100 mg/kg (Alz-ED1) and 200 mg/kg (Alz-ED2) spent less than 47% and 66% of the time, respectively, than the Azheimer's model mice (Alz). Two simple stilbenes, trans-piceatannol and trans-resveratrol, showed selectively inhibitory activity in silico against AChE. Two stilbene dimers, cassigarol E and scirpusin A, exhibited low nanomolar inhibitory potential against AChE and BChE, significantly lower than those of the positive control, donepezil and tacrine. These findings suggest that the stilbenes from P. edulis seeds, particularly the stilbene dimers, warrant further investigation as potential neuroprotective candidates in the prevention of cognitive deficits associated with Alzheimer's disease.
Le Duc Anh, Luu Van Chinh, Truong Ngoc Hung, Nguyen Manh Cuong, and Pham Hong Ngoc
Publishing House for Science and Technology, Vietnam Academy of Science and Technology (Publications)
2’-Hydroxychalcones and murrayafoline A, a natural compounds isolated from Glycomis stenocarpa, have been reported to have the promising anti-cancer activity. In this study, a series of 2'-hydroxychalcones containing murrayafoline A (MuA) 6a-f were achieved by Claisen-Schmidt condensation of the key intermediate 5'-(1-methoxy-3-methyl-carbazolyl)methyl-2'-hydroxyacetophenone 4 with various aldehydes 5a-f with purpose of combining activity of two precusors. Their structures were determined by NMR and MS spectral data. Screening for cytotoxicity of compounds showed that compounds 6a-6d expressed cytotoxic activity, notably compound 6a displayed activity against all tested cell lines LU-1, Hep-G2, MCF-7, P338, and SW480 with the IC50 values ranging from 23.97 to 80.19 μg/mL. Clearly, the substitution at position of N-H group of murrayafoline a led to a decline in the cytotoxicity of the obtained derivatives. This finding suggests the presence of the N-H group might be play a crucial role for the cytotoxicity of the murrayafoline A derivatives.
Feng-Juan Mou, Xiu Hu, Bui Thu Ha, and Nguyen Manh Cuong
Museum National D'Histoire Naturelle
Several phylogenetic studies have revealed that Murraya s. lat. is not monophyletic, suggesting that it should be split into two genera, namely Murraya s. str. and Bergera J.Koenig ex L. Here, the genus Bergera is comprehensively revised based on molecular and morphological data. The genus consists of 11 species in total, including all species previously placed in Murraya sect. Bergera and an additional species previously placed in Murraya sect. Murraya. Ten new combinations are proposed, namely Bergera alternifolia (Kurz) F.J.Mou comb. nov., B. crenulata (Turcz.) F.J.Mou comb. nov., B. euchrestifolia (Hayata) F.J.Mou comb. nov., B. glabra (Guillemin) F.J.Mou comb. nov., B. kwangsiensis (C.C.Huang) F.J.Mou comb. nov., B. macrophylla (C.C.Huang) F.J.Mou comb. nov., B. microphylla (Merr. & Chun) F.J.Mou comb. nov., B. siamensis (Craib) F.J.Mou comb. nov., B. stenocarpa (Drake) F.J.Mou comb. nov., and B. tetramera (C.C.Huang) F.J.Mou comb. nov. An identification key of the 11 species and morphological descriptions are provided, as well as illustrations of diagnostic characteristics. Phylogenetic relationships of the species in Bergera are discussed.
Nguyen Manh Cuong, Ninh The Son, Ngu Truong Nhan, Yoshiyasu Fukuyama, Amer Ahmed, Simona Saponara, Alfonso Trezza, Beatrice Gianibbi, Ginevra Vigni, Ottavia Spiga,et al.
MDPI AG
Hypertension is a risk factor for cardiovascular diseases, which are the main cause of morbidity and mortality in the world. In the search for new molecules capable of targeting KCa1.1 and CaV1.2 channels, the expression of which is altered in hypertension, the in vitro vascular effects of a series of flavonoids extracted from the heartwoods, roots, and leaves of Dalbergia tonkinensis Prain, widely used in traditional medicine, were assessed. Rat aorta rings, tail artery myocytes, and docking and molecular dynamics simulations were used to analyse their effect on these channels. Formononetin, orobol, pinocembrin, and biochanin A showed a marked myorelaxant activity, particularly in rings stimulated by moderate rather than high KCl concentrations. Ba2+ currents through CaV1.2 channels (IBa1.2) were blocked in a concentration-dependent manner by sativanone, 3′-O-methylviolanone, pinocembrin, and biochanin A, while it was stimulated by ambocin. Sativanone, dalsissooside, and eriodictyol inhibited, while tectorigenin 7-O-[β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside], ambocin, butin, and biochanin A increased IKCa1.1. In silico analyses showed that biochanin A, sativanone, and pinocembrin bound with high affinity in target-sensing regions of both channels, providing insight into their potential mechanism of action. In conclusion, Dalbergia tonkinensis is a valuable source of mono- and bifunctional, vasoactive scaffolds for the development of novel antihypertensive drugs.
Vu Thi Thu, Nguyen Manh Cuong, Dao Tran Cao, Luu Tien Hung, and Luong Truc-Quynh Ngan
Elsevier BV
Thuoc Van Doan, Pham Thi Huong, and Tran Huu Phong
Publishing House for Science and Technology, Vietnam Academy of Science and Technology (Publications)
In the present study, a lactic acid producing bacterium was isolated and screened from fermented mustard green. The selected bacterial strain (V156) was classified into genus Lactobacillus. High lactic acid concentration of 101.6 g/L and productivity of 2.82 g/L/h were efficiently achieved by Lactobacillus sp. V156 after 36 h of cultivation in fed-batch fermentation using ammonium hydroxide as the neutralizing agent. The production of high lactic acid in short cultivation time demonstrates that Lactobacillus sp. V156 is a promising strain for L-lactic acid production
Chong-Ling Deng, Chuan-Wu Chen, Xiao-Xiao Wu, Nguyen Manh Cuong, and Feng-Juan Mou
Finnish Zoological and Botanical Publishing Board
A new species, Bergera unifolia C.L. Deng & F.J. Mou (Rutaceae, Aurantioideae, Clauseneae) is described and illustrated from Dahua County, Guangxi Province, China, based on morphological characters as well as on nrDNA (ITS) and cpDNA (trnL-F, atpB-rbcL, rbcL, matK, psbH-petB and psbA-trnH) sequences. It is characterised by unifoliate leaves similar to those of Murraya stenocarpa (Murraya sect. Bergera, or Chalcas sect. Bergera) but differs from it by having smaller and thinner subcoriaceous leaflets with irregularly toothed margins. The leaflets resemble those of M. kwangsiensis (Murraya sect. Bergera) in having hairs under the leaflets, oil glands and similar odour. Based on molecular data, B. unifolia is closely related to M. stenocarpa and M. kwangsiensis and thus it is important for resolving the classification of those species within Murraya sect. Bergera that should be formally transferred to Bergera.
Nguyen Manh Cuong, Dao Tran Cao, Vu Thi Thu, and Luong Truc-Quynh Ngan
Elsevier BV
Abstract In this report, we present the use of surface-enhanced Raman scattering (SERS) in combination with the silver nanodendrites (AgNDs) for direct detection of melamine at low concentrations in liquid milk and infant formula. The fern-like AgNDs were electrochemically deposited onto the surface of silicon. The results showed that the molecular fingerprints of melamine in liquid milk and infant formula could be directly detected with the limit of detection (LOD) as low as 0.1 mg/L in liquid milk and 0.02 mg/L in infant formula without the need for the extraction procedure. A good linear relationship between melamine SERS intensity (at 682 cm−1) and concentration of melamine in liquid milk and infant formula was obtained with the correlation coefficient (R2) reaches 0.9914 and 0.9952, respectively. These results suggest that SERS is a promising analytical method for application in food safety and environmental monitoring.
Nguyen Quoc Binh, Nguyen Thanh Tung, Nguyen Phuong Hanh, Luu Hong Truong, Nguyen Hieu Cuong, Kieu Thi Hoai, Nguyen Viet Than, and Ain Raal
Informa UK Limited
Le Xuan Duy, Vinh Le Ba, Dan Gao, Vu Dinh Hoang, Tran Quoc Toan, Seo Young Yang, Dao Duy Quang, Young Ho Kim, and Nguyen Manh Cuong
Informa UK Limited
Nine bioactive compounds, including one new dihydroisocoumarin glycoside, 3S-thunberginol C 6-O-β-D-glucopyranoside (1a/1b), were isolated by chromatographic separation from the fruits of the Vietnamese medicinal plant Docynia indica (Wall.) Decne. 3S-thunberginol C 6-O-β-D-glucopyranoside was determined as a mixture of boat-like conformers based on NMR evidence and density functional theory (DFT) calculations. The in vitro inhibition of soluble epoxide hydrolase (sEH) by the isolated compounds was comparable to that of AUDA (positive control), yielding IC50 values ranging from 10.0 ± 0.6 to 88.4 ± 0.2 µM. Among isolated compounds, 3-methoxy-4-hydroxy-benzoic acid (7) and 2',6'-dihydroxy 3',4'-dimethoxychalcone (9) were identified as a potent inhibitor of sEH, with IC50 values of 19.3 ± 2.2 and 10.0 ± 0.6 mM, respectively. These results suggest that the fruits of D. indica may be useful as daily supplements for the prevention of cardiovascular and other sEH-related diseases.[Formula: see text].
Luu Hong Truong, Nguyen Hieu Cuong, Tran Huu Dang, Nguyen Thi My Hanh, Vien Le Thi, Hanh Tran Thi Hong, Tran Hong Quang, Hai Dang Nguyen, Cuong Nguyen Xuan, Nam Nguyen Hoai,et al.
Informa UK Limited
Abstract In our search for cytotoxic constituents from Vietnamese plants, the methanolic extract of Isotrema tadungense was found to exhibit significant cytotoxic effect. Subsequent phytochemical investigation of ethyl acetate fractions of this plant led to isolation of 11 compounds including one new arylbenzofuran rhamnoside namely aristolochiaside (1), two aristololactams (2 and 3), three lignanamides (4–6) and five phenolic amides (7–11). Their structures were elucidated by 1 D and 2 D NMR and HR-QTOF-MS experiments. Among the isolated compounds, aristolochiaside (1), aristolactam AIIIa (2) and N-trans-sinapoyltyramine (10) exhibited strong and selective cytotoxicity on the HeLa human cancer cell line with IC50 values of 7.59 ± 1.03, 8.51 ± 1.73 and 9.77 ± 1.25 μM, respectively.
Luu Hong Truong, Nguyen Hieu Cuong, Tran Huu Dang, Trinh Thi My Dung, Pham Thi Cham, Tran Thi Hong Hanh, Tran Hong Quang, Nguyen Hai Dang, Nguyen Xuan Cuong, Nguyen Hoai Nam,et al.
Informa UK Limited
Abstract In our search for anti-inflammatory constituents from Vietnamese plants, the methanolic extract of Helicteres viscida was found to exhibit inhibitory effect on LPS-induced NO production in RAW264.7 cells. Phytochemical investigation of this plant led to isolation of four sulphated flavones (1–4), including one new compound 5,3′,4′-trihydroxy-7-methoxy-8-O-sulphate flavone (1), and two pregnane-type steroids (5 and 6), including one new compound 7-epi-heligenin B (5). Their structures were elucidated by 1D and 2D NMR as well as HR-QTOF-MS experiments. Among isolated compounds, heligenin B (6) exhibited potent inhibitory effect on LPS-induced NO production in RAW264.7 cells with IC50 of 1.23 ± 0.05 µM. The activity of 6 was comparable to that of the positive control cardamonin. Graphical Abstract
Nguyen Trong Dan, Hoang Duc Quang, Vuong Van Truong, Do Huu Nghi, Nguyen Manh Cuong, To Dao Cuong, Tran Quoc Toan, Long Giang Bach, Nguyen Huu Thuan Anh, Nguyen Thi Mai,et al.
Springer Science and Business Media LLC
The addition of chalcone and amine components into indirubin-3′-oxime resulted in 15 new derivatives with high yields. Structures of new derivatives were also elucidated through 1D, 2D-NMR and HR-MS(ESI) spectra and X-ray crystallography. All designed compounds were screened for cytotoxic activity against four human cancer cell lines (HepG2, LU-1, SW480 and HL-60) and one human normal kidney cell line (HEK-293). Compound 6f exhibited the most marked cytotoxicity meanwhile cytotoxicity of compounds 6e , 6h and 6l was more profound toward cancer cell lines than toward normal cell. These new derivatives were further analyzed via molecular docking studies on GSK-3β enzyme. Docking analysis shows that most of the derivatives exhibited potential inhibition activity against GSK-3β with characteristic interacting residues in the binding site. The fast pulling of ligand scheme was then employed to refine the binding affinity and mechanism between ligands and GSK-3β enzyme. The computational results are expected to contribute to predicting enzyme target of the trial inhibitors and their possible interaction, from which the design of new cytotoxic agents could be created in the future.
Nguyen Manh Cuong, Ninh The Son, Ngu Truong Nhan, Pham Ngoc Khanh, Tran Thu Huong, Nguyen Thi Thu Tram, Giampietro Sgaragli, Amer Ahmed, Alfonso Trezza, Ottavia Spiga,et al.
Georg Thieme Verlag KG
Abstract Dalbergia species heartwood, widely used in traditional medicine to treat various cardiovascular diseases, might represent a rich source of vasoactive agents. In Vietnam, Dalbergia tonkinensis is an endemic tree. Therefore, the aim of the present work was to investigate the vascular activity of R-(−)-3′-hydroxy-2,4,5-trimethoxydalbergiquinol isolated from the heartwood of D. tonkinensis and to provide circular dichroism features of its R absolute configuration. The vascular effects of R-(−)-3′-hydroxy-2,4,5-trimethoxydalbergiquinol were assessed on the in vitro mechanical activity of rat aorta rings, under isometric conditions, and on whole-cell Ba2+ currents through CaV1.2 channels (IBa1.2) recorded in single, rat tail main artery myocytes by means of the patch-clamp technique. R-(−)-3′-Hydroxy-2,4,5-trimethoxydalbergiquinol showed concentration-dependent, vasorelaxant activity on both endothelium-deprived and endothelium intact rings precontracted with the α 1 receptor agonist phenylephrine. Neither the NO (nitric oxide) synthase inhibitor Nω-nitro-L-arginine methyl ester nor the cyclooxygenase inhibitor indomethacin affected its spasmolytic activity. R-(−)-3′-Hydroxy-2,4,5-trimethoxydalbergiquinol-induced vasorelaxation was antagonized by (S)-(−)-Bay K 8644 and unaffected by tetraethylammonium plus glibenclamide. In patch-clamp experiments, R-(−)-3′-hydroxy-2,4,5-trimethoxydalbergiquinol inhibited IBa1.2 in a concentration-dependent manner and significantly decreased the time constant of current inactivation. R-(−)-3′-Hydroxy-2,4,5-trimethoxydalbergiquinol likely stabilized the channel in its closed state, as suggested by molecular modelling and docking simulation to the CaV1.2 channel α 1c subunit. In conclusion, D. tonkinensis species may represent a source of agents potentially useful for the development of novel antihypertensive drugs.
Ninh The Son, Midori Suenaga, Yoiichi Matsunaga, Luu Van Chinh, Miwa Kubo, Kenichi Harada, Nguyen Manh Cuong, and Yoshiyasu Fukuyama
Springer Science and Business Media LLC
The vulnerable plant Dalbergia tonkinensis Prain is a rare species in Vietnam. In the course of our studies on biologically active plants, we performed serine protease enzyme screenings. The results suggest that at concentrations of 25–250 ng/mL, methanol extracts of leaf and root, root ethanol extract and its dichloromethane fraction, and heartwood water decoction extract can serve as useful sources to stimulate trypsin enzyme activity. In addition, water decoction extracts of leaf and stem bark may explain unknown ethno-pharmacology due to the high inhibitory effects in enzyme assays using trypsin, chymotrypsin, and elastase. Among 23 isolated compounds and two semi-synthetic derivatives tested, quercetin (17) inhibits the activities of trypsin and chymotrypsin with IC50 9.7 µM. Flavonoids categorized as flavanone, isoflavanone, flavone, isoflavone, pretocarpan, aurone, and neoflavanone demonstrated variable activities. Several substitutions are closely correlated with protease actions, including hydroxylation at C-3 and C-3′ in flavone and C-5 and C-3′ in isoflavone, hydroxylation at C-3, C-5 and C-3′, carboxylation at C-6 and C-8, and 7-substitution in flavanone; 7-substitution and methoxylation at C-3′ in isoflavanone; and lactone ring opening in neoflavanone. In the assessment of casein cleavage, at a dose of 25 ng/mL, leaf water decoction extract demonstrates an inhibitory effect on casein cleavage by trypsin, whereas ethanol and methanol extracts of the root caused activation.
To Dao Cuong, Doan Lan Phuong, Nguyen Van Tuyen Anh, Pham Ngoc Khanh, Tran Thu Huong, and Nguyen Manh Cuong
Publishing House for Science and Technology, Vietnam Academy of Science and Technology (Publications)
The present research was aimed to study the chemical compositions of Passiflora edulis Sims seeds oil, including the fatty acid profiles, contents of tocopherols, sterols, and triglycerides. The seeds oil yield is 24.88% by using Soxhlet method. Passiflora edulis seeds oil showed high levels of unsaturated fatty acids (89.25%) with main ingredient linoleic acid (w-6, 66.94%) and oleic acid (w-6, 18.86%). Tocopherols (18.04 mg/kg), sterols (2935.35 mg/kg) and triglycerides (monomere TAG, 74.11%) are also determined by using IOC and ISO methods, respectively. The findings demonstrate that P. edulis seeds oil could be used beneficially in the food and cosmetic industries.
Ninh The Son, Yoshiyasu Fukuyama, and Nguyen Manh Cuong
Springer Science and Business Media LLC
A new sesquiterpene, rel-(3R,6S,7S)-6α-hydroxycyclonerolidol (1), along with three known compounds, including neroplomacrol (2), naringin (3), and p-formylphenol (4), was isolated from the heartwood of Dalbergia tonkinensis. Their chemical structures were elucidated based on spectroscopic analysis.
Ninh The Son, Mari Kamiji, Tran Thu Huong, Miwa Kubo, Nguyen Manh Cuong, and Yoshiyasu Fukuyama
Springer Science and Business Media LLC
Phytochemical investigations of the leaves and roots of Dalbergia tonkinensis led to the isolation of a new isoflavone glycoside derivative, isocaviunin 7-O-β-D-apiofuranosyl-(1 → 6)-β-D-glucopyranoside (1), and a new scalemic sesquiterpene lactone, 3,7-dimethyl-3-vinylhexahydro-6,7-bifuran-3(2H)-one (2), along with the previously known compounds 3-16, and nine other known compounds 17-25 were isolated from the leaves of Cratoxylum formosum. The chemical structures of the isolated compounds were elucidated by 1D- and 2D-NMR analyses as well as MS spectroscopic data. The results suggest that flavonoids are characteristic of both plants. In the DPPH radical scavenging assay, (3 R)-vestitol (5) and isoquercetin (24) possessed the strongest antioxidative IC50 values of 42.20 µg/mL and 45.63 µg/mL, respectively, and their values were comparable to that of the positive control catechin (IC50 42.98 µg/mL).