Jin-Cherng Huang

Cytotoxic compounds from the stems of Cinnamomum tenuifolium.

Three new butanolides, tenuifolide A (1), isotenuifolide A (2), and tenuifolide B (3), a new secobutanolide, secotenuifolide A (4), and one new sesquiterpenoid, tenuifolin (5), along with 16 known compounds were isolated from the stems of Cinnamomum tenuifolium. Their structures were determined by spectroscopic analyses. Compound 4 was found to induce apoptotic-related DNA damage, increase sub-G1 cells, and inhibit the growth of human prostate cancer cells, DU145. In addition, treatment with 4 significantly increased intracellular H2O2 and/or peroxide. The results show that 4 induced (a) noticeable reduction of mitochondrial transmembrane potential (DeltaPsim); (b) significant increase in the ratio of cytochrome c concentration (cytosol/mitochondria); and (c) subsequent activation of caspase-9/caspase-3. Antiproliferation caused by 4 was found to markedly decrease when pretreated with caspase-9/caspase-3 inhibitor. In ROS scavenging, antioxidant, NADPH oxidase, and NO inhibitor studies, pretreatment of DU145 cells with either DPI, dexamethasone, L-NAME, or mannitol decreased 4-induced intracellular DCF fluorescence of ROS. These results suggest that an increase of H2O2 and/or peroxide by 4 is the initial apoptotic event and 4 has anticancer effects on DU145 cells.

Isolation of new aristolactam and dioxoaporphine from the leaves of Michelia compressa var. lanyuensis (Magnoliaceae)

Pressalanine A (1), a new Michelia aristolactam, and pressalanine B (2), a new Michelia dioxoaporphine, have been isolated from Michelia compressa var. lanyuensis (Magnoliaceae), and these structures were determined on the basis of spectroscopic analysis.

Isolation of a new monoterpenic ester from the leaves of Michelia compressa (Maxim.) Sargent var. formosana Kanehira (Magnoliaceae).

Pressafonin A (1) and pressafonin B (2), two new Michelia monoterpenic esters, have been isolated from Michelia compressa (Maxim.) Sargent var. formosana Kanehira (Magnoliaceae), and their structures are determined on the basis of spectroscopic analysis.

Chemical constituents from the whole plant of Gaultheria itoana Hayata.

Two new diterpenoids, 14,18‐dihydroxyabieta‐8,11,13‐trien‐7‐one (1) and 13‐acetyl‐14,18‐dihydroxy‐podocarpa‐8,11,13‐triene (2), together with eight known compounds, i.e., gaultheric acid (3), vanillic acid (4), 4‐hydroxybenzoic acid (5), cinnamic acid (6), stearic acid (7), palmitic acid (8), β‐sitosterol (9), and stigmasterol (10), were isolated from the MeOH extract of the whole plant of Gaultheria itoana Hayata (Ericaceae). The structures of the new constituents were elucidated by spectroscopic methods (UV, IR, and 1D‐ and 2D‐NMR) and by mass spectrometry (HR‐ESI‐MS). Among them, 1 and 2 were demonstrated to exhibit significant cytotoxic activity against the LNCaP cell line.

Chemical constituents from the leaves of Michelia compressa var. formosana

The genus Michelia (Magnoliaceae) consists of about 30 species. One of the species is native to Taiwan. Michelia compressa var. formosana is an evergreen tree, especially distributed in Taiwan, Japan, and Ryukyu Islands. Michelia species have been used by indigenous peoples for the treatment of cancer. For example, Michelia champaca has been used in India for the treatment of abdominal tumors and M. hypoleuca and M. officinalis for carcinomatous sores and leukemia, respectively, in China [1]. There is only one paper describing a constituent (ceryl alcohol) from the leaves of M. compressa [2]. Recently, we reported four aporphines, one oxoaporphine, two amides, one lignan, two neolignans, one benzenoid and two steroids from the stems of this plant [3]. In continuation of a program studying chemotaxonomy and biologically active components from Magnoliaceous plants [3–7], four aporphines, (–)-anonaine [8], (–)-N-acetylanonaine [9], (–)-N-formylanonaine [10], (–)-N-acetylnornuciferine [11]; two oxoaporphines, liriodenine [8], oxoxylopine [12]; one lignan, (+)-syringaresinol [13]; two amides, N-trans-feruloyltyramine [14], N-cis-feruloyltyramine [15]; seven benzenoids, 4-hydroxybenzaldehyde [16], 4-hydroxybenzoic acid [16], methylparaben [16], syringaldehyde [16], syringic acid [16], eugenol [17], ferulic acid [16]; two chlorophylls, pheophorbide a [18], aristophyll-C [19]; and two steroids, β-sitosterol, stigmasterol [20], are isolated from the leaves of M. compressa. In addition to (–)-anonaine, liriodenine, (+)-syringaresinol, N-trans-feruloyltyramine, N-cis-feruloyltyramine, β-sitosterol, and stigmasterol, all of these compounds were isolated for the first time from this source [21–27]. Anti-oxidant properties elicited by plant species have a full range of perspective applications in human health care. In recent years, the prevention of cancer and cardiovascular diseases has been associated with the ingestion of fresh fruits, vegetables, or teas rich in natural anti-oxidants [28]. Experimental evidence suggests that free radicals and reactive oxygen species (ROS) have been implicated in more than 100 diseases, including malaria, acquired immunodeciency syndrome, heart disease, stroke, arteriosclerosis, diabetes, cancer, and gastric ulcer [29–31]. Anti-oxidants can protect the human body from free radicals and ROS effects and retard the progress of many chronic diseases as well as lipid oxidative rancidity in foods [32, 33]. However, BHA and BHT, the most commonly used anti-oxidants at present, are suspected of being responsible for liver damage and carcinogenesis [34, 35]. Therefore, the exploration and utilization of more effective anti-oxidants and anti-bacterial compounds from natural sources are desired. It has been reported that anti-oxidants and radical scavengers inhibit these processes [36]. The leaves of M. compressa var. formosana were collected from Chiayi County, Taiwan, May 2006. Plant material was identified by Dr. Fu-Yuan Lu (Department of Forestry and Natural Resources College of Agriculture, National Chiayi University). A voucher specimen was deposited in the School of Medicine and Health Sciences, Fooyin University, Kaohsiung County, Taiwan. The air-dried leaves of M. compressa var. formosana (7.3 kg) were extracted with MeOH (50 L × 5) at room temperature, and a MeOH extract (249.5 g) was obtained upon concentration under reduced pressure. The MeOH extract, suspended in H2O (1 L), was partitioned with CHCl3 (2 L × 5) to give fractions soluble in CHCl3 (112.2 g) and H2O (87.3 g).

A new benzodioxocinone from the leaves of Cinnamomum tenuifolium

Investigation of the leaves’ extract of Cinnamomum tenuifolium (Lauraceae) led to the isolation of one novel benzodioxocinone, 2,3-dihydro-6,6-dimethylbenzo-[b][1,5]dioxocin-4(6 H)-one (1). The structure was determined through in-depth spectroscopic and mass-spectrometric analyses. The antioxidant potential was evaluated using the following in vitro method: scavenging of 1,1-diphenyl-2-picrylhydrazyl radical. We also detected the anti-proliferative effect of 1 on human oral cancer cells and its IC50 is 107.7 µM.

A novel homosesquiterpenoid from the stems of Cinnamomum burmanii

A novel homosesquiterpenoid, burmanol (1), along with 16 known compounds, including one triterpenoid, one quinol, two chlorophylls, two coumarins, two steroids, three lignans and five benzenoids were obtained from the stems of Cinnamomum burmanii (Lauraceae). The structures of these compounds were determined on the basis of spectroscopic analysis.

Chemical constituents from the leaves of Cinnamomum burmannii

Cinnamomum burmannii Blume (Lauraceae) is a source of Indonesian cinnamon and is widely used as a spice in Indonesia [1]. The chemical constituents of the leaves of this plant have not yet been reported. Recently, we reported a new amide, cinnabutamine, along with five known amides from the stems of C. burmannii [2]. In the course of screening for biologically and chemically novel agents from Formosan plants in the family Lauraceae [3–12], C. burmannii was chosen for further phytochemical investigation. In this study, the MeOH extract of its leaves was subjected to solvent partitioning and chromatographic separation to afford 11 pure substances. The chemical constituents of the leaves of C. burmannii were separated by column chromatography. Eleven compounds, including squalene (1) [13], ficaprenol-10 (2) [14], methyl vanillate (3) [15], coumarin (4) [16], -sitostenone (5) [17], -sitosterol (6) [17], vanillic acid (7) [15], syringic acid (8) [15], (+)-abscisic acid (9) [18], p-hydroxybenzoic acid (10) [15], and kaempferol-3-O-rhamnoside (11) [19], were isolated from the leaves of C. burmannii. Compounds 1–3, 5–8, 10, and 11 were found for the first time from this plant. The specimen of C. burmannii was collected from Chiayi County, Taiwan in January 2009. A voucher specimen (Cinnamo. 10) was identified by Dr. Fu-Yuan Lu (Department of Forestry and Natural Resources College of Agriculture, National Chiayi University) and deposited in the Department of Medical Laboratory Sciences and Biotechnology, School of Medical and Heath Science, Fooyin University, Kaohsiung, Taiwan. The air-dried leaves of C. burmannii (4.7 kg) were extracted with MeOH (80 L 4) at room temperature, and a MeOH extract (186.4 g) was obtained upon concentration under reduced pressure. The MeOH extract was placed on a silica gel column and eluted with CH2Cl2 gradually enriched with MeOH to afford five fractions. Part of fraction 2 (9.52 g) was subjected to silica gel chromatography by eluting with n-hexane–EtOAc (100:1) and enriched with EtOAc to furnish four further fractions (2-1–2-4). Fractions 2-1 (3.05 g) eluted with n-hexane– EtOAc (60:1) was further purified by silica gel column chromatography using the same solvent system to give squalene (1) (12 mg) and ficaprenol-10 (2) (15 mg). Fractions 2-2 (2.57 g) and 2-3 (1.62 g) eluting with n-hexane–EtOAc (30:1) were further separated by silica gel chromatography to give methyl vanillate (3) (5 mg), and purified by preparative TLC (n-hexane– acetone, 20:1) to give coumarin (4) (19 mg) and -sitostenone (5) (12 mg), respectively. A part of fraction 3 (21.07 g) was subjected to silica gel chromatography by eluting with CH2Cl2–MeOH (100:1) and enriched with MeOH to furnish four further fractions (3-1–3-4). Fraction 3-1 (6.52 g) eluted with CH2Cl2–MeOH (80:1) was further purified by silica gel column chromatography using n-hexane–acetone (10:1) to give -sitosterol (6) (10 mg). Fraction 3-2 (8.73 g) eluting with CH2Cl2– MeOH (60:1) was further purified by silica gel column chromatography using the same solvent system and preparative TLC (n-hexane–acetone, 4:1) to give vanillic acid (7) (6 mg) and syringic acid (8) (5 mg). Fraction 3-3 (0.43 g) was further purified by another silica gel column using n-hexane–acetone (3:1) to obtain (+)-abscisic acid (9) (9 mg). A part of fraction 4 (15.33 g) was subjected to silica gel chromatography eluting with CH2Cl2–MeOH (40:1) and enriched gradually with MeOH to give three fractions (4-1–4-3). Fraction 4-2 (8.21 g) was further separated by silica gel column chromatography using the same solvent system and purified by preparative TLC (CH2Cl2–MeOH, 20:1) to yield p-hydroxybenzoic acid (10) (6 mg). Kaempferol3-O-rhamnoside (11) (8 mg) was further purified on a silica gel column using CH2Cl2–MeOH (10:1) from fraction 4-3.

Secondary Metabolites from the Stems of Capsicum annuum var. conoides

Red pepper, Capsicum annuum (Solanaceae), is used as a spice all over the world. Red pepper is studied actively because its pungent principal component, capsaicin, has a dietary effect, analgesic activity, and antioxidant activity [1]. The pungent principal component of red peppers is a group of acid amides of vanillylamine and C8 to C13 fatty acids, which are known generally as capsaicin [2]. More than 16 other capsaicinoids have been found as minor components [3]. Numerous studies have been done on the red pepper fruit, but there are few studies on stems [2–4]. The chemical constituents of stems of C. annuum L. var. conoides Irish have not yet been reported. This study has shown the isolation of secondary metabolites from the stems of C. annuum var. conoides. To further understand the chemotaxonomy and to continue our search for biologically and chemically novel agents from Solanaceous plants, the stems of C. annuum collected from Chiayi County, Taiwan in March, 2011 were chosen for further phytochemical investigation. The MeOH extract of its plants were subjected to solvent partitioning and chromatographic separation to afford 19 pure substances. The chemical constituents in the plant of C. annuum var. conoides were separated by column chromatography. Investigation of the MeOH extract of the plants has led to the isolation of 21 compounds, 10 amides 1–10, four steroids 11–14, one lignan 15, and six benzenoids 16–21. These compounds were obtained and characterized by comparison of their physical and spectral data (UV, IR, NMR, and MS) with values in the literature. All of these compounds were found for the first time from this species. The specimen of C. annuum var. conoides Irish was collected from Chiayi County, Taiwan in March, 2011. A voucher specimen was characterized by Dr. Jin-Cherng Huang of the Department of Forest Products Science and Furniture Engineering, National Chiayi University, Chiayi, Taiwan and deposited in the School of Medical and Health Sciences, Fooyin University, Kaohsiung, Taiwan. The air-dried stems of C. annuum var. conoides (6.2 kg) were extracted with MeOH (10 L 4) at room temperature, and an MeOH extract (64.3 g) was obtained upon concentration under reduced pressure. The MeOH extract was chromatographed over silica gel using CH2Cl2–MeOH as eluent to produce 10 fractions. Part of fraction 2 (6.52 g) was subjected to silica gel column chromatography by eluting with n-hexane–acetone (50:1) to furnish seven fractions (2-1–2-7). Fraction 2-2 (2.52 g) was further purified by another silica gel column using n-hexane–acetone (10:1) to obtain p-hydroxybenzoic acid (16) (2 mg) and p-hydroxybenzaldehyde (17) [5] (5 mg). Fraction 2-3 (1.86 g) was further purified by another silica gel column using n-hexane–acetone (9:1) to obtain vanillic acid (18) [5] (2 mg) and isovanillic acid (19) [5] (3 mg). Part of fraction 3 (5.12 g) was subjected to silica gel column chromatography by eluting with n-hexane–acetone (40:1), then enriched with acetone to furnish eight fractions (3-1–3-8). Fraction 3-1 (1.24 g) eluted with n-hexane–EtOAc (30:1) was further separated using silica gel column chromatography and preparative TLC (n-hexane–EtOAc, 10:1) to give a mixture of -sitosterol (11) [6] and stigmasterol (12) [6] (37 mg). Fraction 3-2 (1.41 g) was further purified on a silica gel column using the CH2Cl2–MeOH system to obtain (+)-syringaresinol (15) [7] (5 mg), ferulic acid (20) [8] (3 mg), and hydroferulic acid (21) [9] (2 mg).

Chemical Constituents of Liriodendron tulipifera

dealt with several alkaloids andsesquiterpenes [3–11]. Previously, we have isolated three aporphines, one oxoaporphine, three lignans, ten benzenoids, andfour steroids from the leaves of this plant [12]. To further understand the chemotaxonomy and to continue searching forbiologically and chemically novel agents from