Shou-Yuan Wu

A new dihydrochalcone glycoside from the stems of Homalium stenophyllum

Abstract A new dihydrochalcone glycoside, phloretin-4-O-β-D-glucopyranoside (1), together with seven known flavonoids (2–8), were isolated from the stems of Homalium stenophyllum. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. The known compounds (2–8) were isolated from the genus Homalium for the first time. All compounds were evaluated for their antibacterial activities against six pathogenic bacteria in vitro.

Bioactive Phenolic and Isocoumarin Glycosides from the Stems of Homalium paniculiflorum

Two new phenolic glycosides (1 and 2) and two new isocoumarin glycosides (3 and 4), along with 14 known compounds (5–18), were isolated from the stems of Homalium paniculiflorum. Their structures were established on the basis of extensive spectroscopic analyses and chemical methods. All new compounds were evaluated for their anti-inflammatory activities via examining the inhibitory activity on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in mouse macrophage RAW 264.7 cells in vitro. Compounds 1 and 4 exhibited inhibitory activities with IC50 values of 30.23 ± 1.23 μM and 19.36 ± 0.19 μM, respectively.

One new berberine from the branches and leaves of Polyalthia obliqua Hook.f. & Thomson

Abstract One new alkaloid consanguine B (1), together with 10 known alkaloids (2–11), were isolated from ethanol extract of the branches and leaves of Polyalthia obliqua Hook.f. & Thomson collected in the Hainan Province, China. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. All compounds were evaluated for their cytotoxic activities. Compound 1 showed weak cytotoxic activities against Hela and MCF-7 human cancer cell lines.

Biologically active oligostilbenes from the stems of Vatica mangachapoi and chemotaxonomic significance

Abstract Phytochemical investigation of the stems of Vatica mangachapoi (Dipterocarpaceae) led to the isolation and structural elucidation of twenty-seven oligostilbenes (1–27), including a new natural compound 1. The structure of 1 was elucidated on the basis of spectroscopic analyses including NMR, MS and ECD data, and the known compounds were identified by comparisons with those reported in the literature. The absolute configuration of 1 was first time determined by a combination of NOESY spectrum and quantum chemical computation. Among of isolates were tested for their anti-osteoporosis and anti-HIV-1 activities in vitro by the MTT method. Moreover, the chemotaxonomic significance of these compounds was summarised.

A new norisoprenoid from the leaves of Ficus pumila

Abstract One new norisoprenoid 3,9-dihydroxy dihydro actinidiolide (1), together with eleven known compounds (2–12), were isolated from ethanol extract of the leaves of Ficus pumila collected in Hainan Province, China. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1, 2, 4, 5, 8 and 10–12 were isolated from the F. pumila for the first time. All compounds were evaluated for their cytotoxic activity. Compounds 3 and 9 showed weak cytotoxic activity against Hela, MCF-7 and A549 cell lines.

A new morphinandienone alkaloid from the stems of Fissistigma tungfangense

Abstract A new morphinandienone alkaloid, fissistigmine A (1), together with three known alkaloids (2−4), were isolated and identified from the stems of Fissistigma tungfangense. Among them, fissistigmine A (1) represents the first example of a novel naturally occurring morphinandienone alkaloid with a unique cleavage of the C-9−N-17 bond. All isolated compounds were evaluated for their anti-rheumatoid arthritis activities via examining their anti-proliferative effects on synoviocytes in vitro. Compound 1 exhibited inhibitory effect on the proliferation of synoviocytes with an IC50 value of 114.6 ± 2.2 μM.

Resveratrol Oligomers from the Stem Bark of Vatica mangachapoi

Vatica, a genus comprising about 65 species, belongs to the largest subfamily Dipterocarpoideae in the family Dipterocarpaceae, most of which are tall, hardy, and evergreen trees primarily distributed throughout Southeast Asia, especially in Indonesia and Malaysia [1], south and east India, and Sri Lanka. This genus is well documented to be a rich source of biologically active resveratrol oligomers. As a phytoestrogen, resveratrol and its oligomers have recently attracted attentions because of their multifunctional bioactivities that may account for its possible cardioprotective action, including smooth muscle cell proliferation and platelet aggregration [2], chemoprevention of cancers [3], activation of human SIRT1 [4], and anti HIV effect [5]. Because of its pharmacological functions, resveratrol and its oligomers are now gaining scientific attention as a longevity promoter. Vatica mangachapoi, a large and rather rare species, occurs only in Hainan Island in China and is used as a disinfection, against hepatitis, and in the extraction of borneol. Although Vatica species have been reported to possess a diversity of polyphenols and biological activities, there have been rare reports of phytochemical investigations or biological activity of this plant [6]. In an attempt to screen the biologically active fractions and compounds from tropical medicinal plants [7], a preliminary screening of successive petroleum ether, EtOAc, and H2O extracts of the stem bark of V. mangachapoi for antioxidant activities was made to measure their free-radical-scavenging effects using the DPPH free radical method [8, 9]. The EtOAc and H2O extracts showed good antioxidant capacity, with IC50 values of 54.4 and 32.7 μM, respectively. Further chemical investigations of the EtOAc extract led to the isolation of 15 resveratrol oligomers, including parviflorol (1) [10], diptoindonesin D (2) [11], eight resveratrol dimers vaticahainol (3) [6], vitisinol G (4) [12], malibatol A (5) [13], vaticahainol C (6) [6], ampelopsin A (7) [14], balanocarpol (8) [10], ampelopsin F (9) [15], and isoampelopsin (10) [16], two resveratrol tetramers vaticaffinol (11) [17] and isohopeaphenol A (12) [18], two resveratrol dimers O-glucosides cordifoloside B (13) [19] and vatalbinoside D (14) [20], and one resveratrol trimer O-glucoside paucifloroside B (15) [21]. These compounds were characterized by spectral data and comparison with those reported in the literature. The three resveratrol oligomers O-glucosides (13–15) were firstly isolated from Shorea cordifolia [19], V. albiramis [20], and V. pauciflora [21], respectively, and recently from V. mangachapoi, which was the second time that these resveratrols were isolated from a natural source. It is also the first report of resveratrol oligomer O-glucosides isolated from V. mangachapoi. Thus, resveratrol oligomers (1–15) isolated from Vatica species could be chemotaxonomic markers for the Vatica genus. The stem bark of V. mangachapoi was collected in Changjiang County, Hainan Province, P. R. China in July 2011. It was identified by Ass. Prof. Zhong Qiong-xin. The voucher specimen has been deposited at the Key Laboratory of Tropical Medicinal Plant Chemistry of the Ministry of Education, Hainan Normal University, Haikou, Hainan, P. R. China. The air-dried powder of the stem bark of V. mangachapoi (10.0 kg) was exhaustively extracted three times with 85% EtOH–H2O at room temperature to afford a crude extract (1.2 kg). The extract was suspended in H2O and then partitioned successively with petroleum ether and EtOAc.

Bioactive Flavonoid Derivatives from Scutellaria luzonica

Scutellaria is one of the most widely used traditional Chinese herbal medicines, and the other name is “HuangQin” in Chinese [1]. Its root is the traditional medicinal part and has been listed in the Chinese Pharmacopoeia for a long time [2]. The aerial parts of Scutellaria also have diverse and strong therapeutic functions and potentially beneficial effects, such as cardiovascular [3], neuroprotective [4], antitubercular [5], memory improving [6], antitumor [7], and antibacterial activity [8]. There have been previous investigations on the chemical constituents of the roots of Scutellaria luzonica Rolfe, and 18 flavonoids, including 13 flavones, two flavanones, one chalcone, and one flavone glycoside, were isolated from this plant [9]. However, Scutellaria luzonica is a variant of Scutellaria luzonica, and the chemical constituents and bioactivities of S. luzonica have not been reported. In order to search for the bioactive chemical constituents of S. luzonica, 14 flavonoid derivatives were isolated from the EtOAc extract of S. luzonica. The isolated compounds were identified as 5-hydroxy-7-methoxyflavanone (1) [10], 6-methoxynaringenin (2) [11], 5,6,7,4 -tetrahydroxyflavanone (3) [12], 5,7,2 -trihydroxyflavone (4) [13], 5,7-dihydroxyflavone (5) [14], hispidulin (6) [15], 5,7,8-trihydroxyl-6-methoxyflavone (7) [16], wogonin (8) [17], 5,6-dihydroxy-7-methoxyflavone (9) [18], 5,7,3 ,4 -tetrahydroxyflavone (10) [19], baicalein (11) [20], oroxylin A (12) [21], 5,8-dihydroxy-7-methoxyflavone (13) [22], and 5,7,2 -trihydroxy-8-methoxyflavone (14) [23], on the basis of their spectroscopic data and by comparison with those previously reported in the literature. All compounds were isolated from S. luzonica for the first time. The biological activity of all the isolated compounds was evaluated against seven pathogenic bacteria, including Candida albicans, Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Escherichia coli, Vibrio parahaemolyticus and V. alginolyticus; Antimosquito larva activity was also tested. Compounds 8 and 11 showed significant antibacterial activity against C. albicans with the same MIC values of 4.17 g/mL. Compounds 8, 10, and 11 showed strong antibacterial activity against V. parahaemolyticus with the same MIC values of 3.12 g/mL. Compounds 8, 11, and 12 showed significant antibacterial activity against V. alginolyticus with the same MIC values of 6.25 g/mL. The other compounds showed weak or no antibacterial activity with MIC values greater than 10 g/mL (Table 1). Compounds 5, 12 and 14 showed Antimosquito larva activity with LC50 values of 50, 30, and 100 g/mL, respectively. General. 1D (1H, 13C, DEPT) and 2D (1H–1H COSY, NOESY, HMQC, HMBC) NMR spectra were recorded on a Bruker AV 400 NMR spectrometer. ESI-MS spectra were recorded on an Agilent 1200 series HPLC interfaced to a Bruker Esquire 6000 Ion Trap mass spectrometer equipped with an electrospray ionization source. HPLC separation was performed on an Agilent-HPLC column (Eclipse XDB-C18, 10 250 mm, 5 m). Silica gel and GF254 were obtained from the Qingdao Marine Chemical Factory. Sephadex LH-20 was manufactured by Pharmacia Co. Ltd. Plant Material. The dried whole plants of Scutellaria luzonica Rolfe were collected in Ledong County, Hainan Province, China, in September 2014 and were identified by Dr. Rongtao Li, Hainan Branch of the Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College. A voucher specimen has been deposited in the Key Laboratory of Tropical Medicinal Plant Chemistry of the Ministry of Education, Hainan Normal University. Extraction and Isolation. The dried whole plants of Scutellaria luzonica (2 kg) were powdered and refluxed with 85% EtOH three times. Evaporation of the solvent under reduced pressure gave the ethanolic extract (55 g), which was dissolved in water and then extracted with petroleum ether and ethyl acetate successively at room temperature.

One new lignan derivative from the Combretum alfredii Hance

Abstract One new lignan derivative 2,3-dimethyl-4-(4-methoxyphenyl)-6,7-dihydroxynaphthalene (1), together with five known compounds (2–6), were isolated from ethanol extract of the branches and leaves of Combretum alfredii Hance collected in Hainan Province, China. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1, 2, 5 and 6 were isolated from the genus of Combretum for the first time. All compounds were evaluated for their antibacterial activities. Compounds 1 and 2 showed significant antibacterial activities against six pathogenic bacteria.