Hung-Yi Huang

Constituents of the Root Wood of Zanthoxylum wutaiense with Antitubercular Activity

Bioassay-guided fractionation of the root wood of Zanthoxylum wutaiense led to the isolation of 11 new compounds, wutaiensol methyl ether (1), demethoxywutaiensol methyl ether (2), methyl wutaiensate (3), methyl 7-hydroxyanodendroate (4), methyl 7-methoxyanodendroate (5), wutaifuranol (6), 7-methoxywutaifuranol (7), 7-methoxywutaifuranal (8), methyl wutaifuranate (9), methyl 7-methoxybenzofuran-5-carboxylate (10), and wutaipyranol (12), together with another 37 known compounds, of which one, 7-methoxybenzofuran-5-carboxaldehyde (11), was not previously known as a plant constituent. The structures of these isolates were identified by means of spectroscopic analysis. Five of these isolates were found to be antitubercular constituents, namely, methyl 7-methoxyanodendroate (5), 7-methoxywutaifuranal (8), wutaiensal (13), dictamnine (14), and gamma-fagarine (15), which exhibited antitubercular activity against Mycobacterium tuberculosis H37Rv, showing MIC values of 35, 35, 30, 30, and 30 microg/mL, respectively.

A novel dimeric coumarin analog and antimycobacterial constituents from Fatoua pilosa.

One novel dimeric coumarin analog, fatouapilosin (1), together with 18 known compounds, have been isolated from the whole plants of Fatoua pilosa. The structures of these isolates were elucidated by means of spectroscopic techniques (UV, IR, MS, 1H‐ and 13C‐NMR, DEPT, COSY, NOESY, HSQC, HMBC, and MS analyses). Among the tested compounds 2–14, scopoletin (3), isobavachalcone (12), and (E)‐1‐[2,4‐dihydroxy‐3‐(3‐methylbut‐2‐enyl)phenyl]‐3‐(2,2‐dimethyl‐8‐hydroxy‐2H‐benzopyran‐6‐yl)prop‐2‐en‐1‐one (14) exhibited the strongest antimycobacterial activities against Mycobacterium tuberculosis H37Rv, with MIC values of 42, 18, and 30 μg/ml, respectively.

Secondary metabolites from the roots of Neolitsea daibuensis and their anti-inflammatory activity.

Bioassay-guided fractionation of the roots of Neolitsea daibuensis afforded three new β-carboline alkaloids, daibucarbolines A-C (1-3), three new sesquiterpenoids, daibulactones A and B (4 and 5) and daibuoxide (6), and 20 known compounds. The structures of 1-6 were determined by spectroscopic analysis and single-crystal X-ray diffraction. Daibucarboline A (1), isolinderalactone (7), 7-O-methylnaringenin (8), and prunetin (9) exhibited moderate iNOS inhibitory activity, with IC₅₀ values of 18.41, 0.30, 19.55, and 10.50 μM, respectively.

Secondary metabolites from the roots of Litsea hypophaea and their antitubercular activity.

Bioassay-guided fractionation of the roots of Litsea hypophaea led to the isolation of seven new butanolides, namely, litseakolides H-N (1-7), all with the 3R,4S configuration, as well as three new biarylpropanoids, hypophaone (8), hypophaol (9), and hypophane (10), and 15 known compounds. The structures of 1-10 were determined by means of spectroscopic analysis. Litseakolide L (5) and N-trans-feruloylmethoxytyramine (11) showed antitubercular activity against Mycobacterium tuberculosis strain H(37)Rv, with MIC values of 25 and 1.6 microg/mL, respectively.

Neolignans and phenylpropanoids from the roots of Piper taiwanense and their antiplatelet and antitubercular activities.

Bioassay-guided fractionation of roots from Piper taiwanense led to isolation of three neolignans, diallylcatechol (1) and neotaiwanensols A, B (2, 3), two diphenylpropanoid ethers, taiwandimerols A, B (4, 5), with one phenylpropanoid, 2,3-diacetoxy-1-methoxy-5-allylbenzene (6), previously unknown in nature, together with 18 known compounds (7-24). Their structures were elucidated by spectroscopic evidence. Among the isolates, hydroxychavicol acetate (7), and 4-allylcatechol (8) showed potent inhibitory activities against platelet aggregation induced by collagen, with IC50 values of 2.1, and 5.3 μM, respectively. Hydroxychavicol acetate (7), 4-allylcatechol (8), and trans-caffeicaldehyde (9) showed antitubercular activities against Mycobacterium tuberculosis H37Rv, with MIC values of 30.3, 27.6, and 25.5 μg/mL, respectively.

Chemical constituents and antitubercular activity of Formosan Pisonia umbellifera.

Bioassay-guided fractionation of the methanolic extract of the stem of Pisonia umbellifera (Nyctaginaceae) afforded the three new compounds, secopisonic acid (1), 6,8-dimethylisogenistein (2), and (+)- ENT-ficusol (3), and four first isolates from nature, pisoninol I (4), pisoninol II (5), pisoquinoline (6), and pisodienone (7), together with fifteen known compounds. Their structures were elucidated by analysis of spectroscopic data. Seven of these isolates, 3, 7, 12, 16, 18, 20, and 21 showed antitubercular activities against Mycobacterium tuberculosis H37R (V) in vitro, with MIC values ≤ 50 µg/mL.

Prenyl Coumarins from Fatoua pilosa.

Six new prenylcoumarins, (+)-fatouain A (1), (-)-fatouain B (2), (+)-fatouain C (3), (-)-fatouain D (4), (+)-fatouain E (5), and (-)-fatouain F (6), along with two new bis-prenylcoumarins, (+)-fatouain G (7) and (+)-fatouain H (8), have been isolated from whole plants of Fatoua pilosa. The relative configurations of 1, 3, and 4 were confirmed by their acetonides on the basis of NOEDIF experiments, the results providing additional support for the relative configurations of 2, 5, 6, 7, and 8.

Secondary Metabolites from the Root Wood of Zanthoxylum wutaiense and Their Antitubercular Activity

Bioassay‐guided fractionation of the root wood of Zanthoxylum wutaiense led to the isolation of five new compounds, wutaipyranol A (1), 8‐methoxywutaipyranol A (2), demethoxywutaiensal (3), demethoxywutaiensol (4), and dihydrodemethoxywutaiensol (5), together with six known compounds. Their structures were elucidated by 1D‐ and 2D‐NMR, as well as MS analyses. Among the isolates, wutaipyranol A (1), 8‐methoxywutaipyranol A (2), and demethoxywutaiensal (3) exhibited antitubercular activities against Mycobacterium tuberculosis H37Rv in vitro, with MIC values of 52.4, 55.6, and 45.8 μg/ml, respectively.

Three New Phenylpropanoids from the Roots of Piper taiwanense and Their Inhibitory Activities on Platelet Aggregation and Mycobacterium tuberculosis

Bioassay‐guided fractionation of the active AcOEt‐soluble fraction from the roots of Piper taiwanense has led to the isolation of two new phenylpropanoids, taiwanensols A and B (1 and 2, resp.), a new natural product, taiwanensol C (3), and 3‐acetoxy‐4‐hydroxy‐1‐allylbenzene (4). The compounds were obtained as two isomer mixtures (1/2 and 3/4, resp.). Their structures were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR spectroscopy and mass spectrometry, and by the comparison of their NMR data with those of related compounds. Compounds 1–4 were evaluated for their antiplatelet and antitubercular activities. The mixtures 1/2 and 3/4 showed potent inhibitory activities against platelet aggregation induced by collagen, with IC50 values of 35.2 and 8.8 μM, respectively. In addition, 1/2 and 3/4 showed antitubercular activities against Mycobacterium tuberculosis H37Rv, with MIC values of 30.0 and 48.0 μg/ml, respectively.