Jinhe Jiang

A new ent-kaurane diterpenoid from Ixora amplexicaulis.

A new ent-kaurane diterpenoid, 6α,16α-dihyroxy-ent-kaurane (1), was isolated from the stems of Ixora amplexicaulis, together with (24R)-6β-hydroxy-24-ethyl-cholest-4-en-3-one (2), 7β-hydroxysitosterol (3), maslinic acid (4), 3,3′-bis(3,4-dihydro-4-hydroxy-6-methoxy-2H-1-benzopyran) (5) and protocatechuric acid (6). Their structures were established by extensive spectroscopic analysis, including 2D NMR techniques. Compounds 2–5 were isolated from the genus Ixora for the first time and 6 obtained originally from I. amplexicaulis.

Horsfiequinones A–F, Dimeric Diarylpropanoids from Horsfieldia tetratepala

A new diarylpropanoid, horsfiequinone A (1), and five new dimeric diarylpropanoids with 1,4-p-benzoquinone residue, horsfiequinones B-F (2-6), along with a known compound, combrequinone B (7), were isolated from Horsfieldia tetratepala. Their structures were elucidated by means of spectroscopic analysis. Horsfiequinones B-F (2-6), isolated as enantiomer mixtures with unequal proportions, were verified by analysis on a chiral OD-H HPLC column. Cytotoxicity evaluation against five human tumor lines showed selective inhibitory effects on HL-60 for several compounds tested with IC50 values ranging from 3.18 ± 0.67 to 6.61 ± 0.08 µM.

Chemical constituents of Dendrobium cariniferum

Considerable studies have been done on plants of the Dendrobium species (Orchidaceae), which are used as a tonic to nourish stomach, promote secretion of saliva, and reduce fever [1], and which yielded alkaloids, fluorenones, sesquiterpenoids, bibenzyls, and phenanthrenes with antitumor, antiplatelet aggregation, antioxidant, and antimutagenic activities [2–8]. D. cariniferum Rchb. f. is distributed in India, Burma, Thailand, Laos, Vietnam, and Yunnan of southwestern China [9]. Previously there was no report on its chemical constituents. In the course of our search for bioactive natural products from medicinal plants in Yunnan of China, we investigated the plant. D. cariniferum was collected from Lianghe County of Yunnan, China in February, 2006. The air-dried whole plants (1.3 kg) were chopped and exhaustively extracted with 95% EtOH. Water was added to the EtOH extract (50 g), and it was then extracted with chloroform to afford chloroform extract (26 g), which was applied to a silica gel column, eluting with petroleum ether, EtOAc, acetone, and MeOH successively to obtain four elutions. The petroleum ether elution (4 g) was crystallized to yield 4 (0.8 g). The EtOAc elution (15 g) was subjected to a silica gel column, eluting with petroleum ether containing increasing amounts of EtOAc to offer five fractions (A-E). Fraction B (7 g) was further separated on column chromatography (silica gel, petroleum ether–EtOAc 4:1; then Sephadex LH-20, MeOH) to yield 1 (25 mg) and 2 (14 mg). Fraction C (2 g) was subjected to Sephadex LH-20 chromatography (MeOH) and then to PTLC (silica gel, CHCl3–MeOH 20:1) to offer 3 (24 mg). Fraction D (3 g) was purified on Sephadex LH-20 chromatography (MeOH) and then crystallized to afford 5 (86 mg).

A New Chalcone Glycoside from Combretum griffithii

A new chalcone glycoside, 2′,4,4′,6′-tetrahydroxydihydrochalcone 2′-O-α-L-rhamnopyranosyl-(1 → 6)-β-Dglucopyranoside (1), was isolated from Combretum griffithii Huerck et M.-A. along with the known compounds (–)-epigallocatechin (2), 3′-O-methyl-(–)-epicatechin (3), (–)-4′-O-methyl epigallocatechin (4), (–)-epicatechin (5), (+)-catechin (6), betulin (7), maslinic acid (8), oleanolic acid (9), arjunolic acid (10), sitoindoside I (11), glycerol 1-(9Z,12Z-octadecadienoate) (12), β-sitosterol (13), and daucosterol (14). Their structures were elucidated by spectroscopic means and comparison with published data. All the compounds were isolated from Combretum griffithii for the first time.

A New Lathyrane Diterpenoid Ester from Euphorbia Dracunculoides

A new lathyrane diterpenoid ester, euphordracunculin C (1), together with a phenolic amide, 4-hydroxy-N-[3-(4-hydroxy-3-methoxyphenyl)-1-oxo-2-propen-1-yl]-3-methoxybenzamide (2), was isolated from the aerial parts of Euphorbia dracunculoides. The structure of the new compound was elucidated on the basis of spectroscopic analysis including 1D and 2D NMR techniques.

Isolation of a new lycodine alkaloid from Lycopodium japonicum

A new lycodine alkaloid, N-methylhydroxypropyllycodine (1), was isolated from the club moss Lycopodium japonicum Thunb, together with five known compounds, N-methyllycodine (2), huperzinine (3), β-obscurine (4), α-obscurine (5) and des-N-methyl-α-obscurine (6). Their structures were elucidated by spectroscopic analyses, including 2D NMR techniques.

Flavonoids from the Fern Pronephrium penangianum

The genus Pronephrium (Abacopteris) belongs to the Thelypteridaceae and comprises approximately 61 species that are found in tropical and subtropical zones of Asia [1]. Earlier research regarding the chemical constituents of the Thelypteridaceae species revealed the presence of an array of structurally interesting compounds, including unusual C-methylflavonoids such as flavan-4-ol glucosides, 3-deoxyanthocyanins, and flavones with a modified B-ring [2–5]. Pronephrium penangianum is widely distributed in the south of China and has been used as a folk medicine for releasing swelling analgesia, removing stasis, and promoting fracture healing [6]. Previous investigation on the constituents of the plant has isolated a lot of compounds such as flavan-4-ol glucosides, anthocyanidins, flavones, phenylpropanoids, and steroids, and some of the compounds were found to possess antioxidant, antiradical, anti-benign prostatic hyperplasia, anti-inflammatory, hypolipidemic, vascular protective, and neuroprotective activities [2, 7–12]. To find of further active principles from P. penangianum, we investigated the plant. The whole plant of P. penangianum was collected from Kunming, Yunnan Province of China in February 2006 and identified by Prof. Shugang Lu (Yunnan University). A voucher specimen of this collection (No. 2006027) was deposited at the Herbarium of Yunnan University, Kunming, China. The dried powdered whole plant of P. penangianum (500 g) was extracted with 95% EtOH (4 2.5 L) at room temperature. The EtOH extract was evaporated in vacuo to yield a dark brown residue (50 g). Water (0.5 L) was added to the residue, and the resulting solution was extracted with EtOAc and n-BuOH successively (4 0.5 L). Evaporation of the respective solvents gave EtOAc (13 g) and n-BuOH (18 g) extracts. The EtOAc extract was separated on a silica gel column eluted with petroleum ether containing increasing amounts of EtOAc to offer six fractions. Fraction 2 (380 mg) was chromatographed over silica gel (CHCl3–acetone 10:1) to furnish 9 (258 mg) and 11 (6 mg). Fraction 3 (2 g) was isolated on a silica gel column eluted with CHCl3–acetone (from 10:1 to 1:1) and then on preparative TLC developed with CHCl3–CH3OH (5:1) to yield 7 (10 mg) and 8 (12 mg). Fraction 4 (210 mg) was subjected to MCI column chromatography (MeOH–H2O 7:3 9:1) to afford three subfractions (F4.1–F4.3). Compound 10 (78 mg) was crystallized from F4.1 (110 mg) with MeOH. Fraction 4.2 (45 mg) was further purified on a Sephadex LH-20 column (MeOH) to yield 1 (10.0 mg).

Phenolics from Claoxylon longifolium

The Euphorbiaceae species are a prolific source of new diterpenoids with diverse skeletons, of which some have many different activities such as antitumor, antiproliferative, and antimicrobial effects [1, 2]. Claoxylon longifolium (Euphorbiaceae) is distributed in Southeastern Asia, India, and Yunnan of southwestern China [3]. Previously, there was no phytochemical study on the plants of Claoxylon genus. In the course of our search for bioactive natural products from medicinal plants in Yunnan of China, we investigated the plant. C. longifolium was collected from Xishuangbanna of Yunnan, China in October, 2009. The air-dried stems (8.2 kg) were chopped and exhaustively extracted with MeOH. Water (3.5 L) was added to the MeOH extract, and the resulting solution was partitioned with EtOAc and n-BuOH successively (six times, each 3.0 L). The EtOAc extract (116 g) was separated on a silica gel column, eluting with petroleum ether containing increasing amounts of EtOAc to afford 8 fractions. Fraction E (8.3 g) was repeatedly subjected to CC over silica gel (CHCl3–MeOH 50:1–0:1), MCI (gel CHP-20P) (MeOH–H2O 9:1–1:0) and Sephadex LH-20 (MeOH–CHCl3 2:3) to furnish 4 (51 mg), 5 (15 mg), 6 (6 mg), 8 (5 mg), and 9 (2 mg). Fraction F (26.5 g) was subjected to repeated CC, first on silica gel (CHCl3–MeOH 30:1–0:1) and then on Sephadex LH-20 (MeOH–CHCl3 2:3 and 1:0) to afford 1 (7 mg), 2 (10 mg), 3 (5 mg), and 7 (5 mg). Compound 1, C20H18O8, white powder. The ESI-MS exhibited peaks for ions at m/z 387 [M + H] +. PMR spectrum (500 MHz, C5D5N, , ppm, J/Hz): 7.74 (1H, d, J = 9.5, H-4), 7.41 (1H, d, J = 2.0, H-2 ), 7.34 (1H, dd, J = 2.0, 8.0, H-6 ), 7.28 (1H, d, J = 8.0, H-5 ), 6.72 (1H, s, H-5), 6.43 (1H, d, J = 9.5, H-3), 3.78 (3H, s, 6-OCH3), and 3.69 (3H, s, 3 -OCH3), and four oxygenated protons at 5.58 (1H, d, J = 8.0, H-7 ), 4.46 (1H, m, H-8 ), 4.30 (1H, dd, J = 2.4, 12.8, H-9 a), 3.90 (1H, dd, J = 3.2, 12.8, H-9 b). 13C NMR and DEPT spectra (125 MHz, C5D5N, , ppm): 160.9 (C-2), 113.9 (C-3), 144.6 (C-4), 101.1 (C-5), 146.5 (C-6), 138.5 (C-7), 133.1 (C-8), 139.4 (C-9), 111.9 (C-10), 127.7 (C-1 ), 112.3 (C-2 ), 149.2 (C-3 ), 148.9 (C-4 ), 116.7 (C-5 ), 121.8 (C-6 ), 77.6 (C-7 ), 80.0 (C-8 ), 60.8 (C-9 ), 56.2 (6-OCH3), and 55.9 (3 -OCH3). Based on the NMR spectral data and comparison of the spectral data with those reported in literature, 1 was identified as cleomiscosin A [4]. Compound 2, C21H20O9, white powder. The ESI-MS exhibited peaks for ions at m/z 417 [M + H] +. PMR spectrum (500 MHz, C5D5N, ppm, J/Hz): 7.74 (1H, d, J = 9.5, H-4), 6.73 (1H, s, H-5), 6.44 (1H, d, J = 9.5, H-3), 6.72 (2H, s, H-2 , 6 ), 3.78 (3H, s, 6-OCH3), 3.76 (6H, s, 3 , 5 -OCH3), 5.59 (1H, d, J = 8.1, H-7 ), 4.38 (1H, m, H-8 ), 4.33 (1H, dd, J = 2.4, 12.8, H-9 a), 3.92 (1H, dd, J = 3.2, 12.8, H-9 b). 13C NMR and DEPT spectra (125 MHz, C5D5N, , ppm): 160.9 (C-2), 113.9 (C-3), 144.6 (C-4), 101.1 (C-5), 146.5 (C-6), 138.6 (C-7), 133.2 (C-8), 139.4 (C-9), 112.0 (C-10), 126.5 (C-1 ), 106.5 (C-2 , 6 ), 149.4 (C-3 , 5 ), 135.8 (C-4 ), 77.9 (C-7 ), 80.0 (C-8 ), 60.8 (C-9 ), 56.4 (3 , 5 -OCH3), and 56.2 (6-OCH3). Based on the NMR spectral data and comparison of the spectral data with those reported in the literature, 2 was identified as cleomiscosin C [4].

Chemical Constituents of Pteris fauriei

The group of ferns from the genus Pteris (Pteridaceae) contains 300 cosmopolitan species, with 66 species being endemic to China [1]. Several plants in the genus are widely used in traditional Chinese medicine for relieving internal heat or fever, swelling and diarrhea, and removing toxicity [2, 3]. Previously, phytochemical investigations on the Pteris genus had led to the isolation of various phenolic compounds, flavonol glycosides, kauranes, and pterosin sesquiterpenes [4–8]. Some extracts and compounds of plants in the genus showed various bioactivities such as antitumor, antibacterial, cytotoxic, and free radical-scavenging activities [9–11]. P. fauriei Hieron. is distributed in North Vietnam, Japan, and southern China. There have been no reports on the isolation of compounds from it. During the search for bioactive compounds from medicinal plants in Yunnan of China, we investigated the plant. P. fauriei was collected from Kunming of Yunnan, China in April, 2006. The air-dried whole plants (0.8 kg) were chopped and exhaustively extracted with 95% EtOH. Water (1.5 L) was added to the EtOH extract (100 g), and the resulting solution was extracted with petroleum ether and EtOAc successively (four times, each 0.8 L). The EtOAc extract (27 g) was separated on a silica gel column and eluted with petroleum ether containing increasing amounts of EtOAc to obtain nine fractions. Fraction B (4.2 g) was subjected to repeated column chromatography (silica gel, petroleum ether–EtOAc, 20:1) to afford 6 (47 mg). Fraction C (7.1 g) was isolated on a Sephadex LH-20 column (CHCl3–MeOH, 3:2) to give 5 (13 mg). Fraction D (1.3 g) was chromatographed over preparative TLC (petroleum ether–EtOAc, 3:1) to furnish 1 (8 mg). Fraction E (1.8 g) was purified on a Sephadex LH-20 column (MeOH) to obtain 2 (3 mg) and 3 (4 mg). Fraction F (1.5 g) was subjected to Sephadex LH-20 column chromatography (MeOH) to afford 4 (15 mg). Fraction G (4.7 g) was chromatographed over silica gel (CHCl3–Me2CO, 20:1) and then purified by chromatography over Sephadex LH-20 (MeOH–H2O, 9:1) to furnish 7 (43 mg). Fraction H (5.2 g) was isolated on MCI gel and eluted with a gradient of 0–100% MeOH in H2O to obtain 8 (16 mg). Aristolone (1), C15H22O, colorless amorphous powder. The mass spectrum exhibited peaks for ions at m/z 218 (M+, 43), 203, 191, 177, 161, 147, 91. PMR spectrum (CDCl3, , ppm, J/Hz): 1.19, 1.20, 1.30 (each 3H, s), 1.06 (3H, d, J = 6.7), 5.75 (1H, s). 13C NMR and DEPT spectra (CDCl3, , ppm): 196.6, 167.9, 124.7, 40.0, 39.6, 39.1, 35.9, 33.5, 31.0, 30.1, 26.5, 24.7, 22.9, 16.9 and 16.6 [12]. Kaempferol (2), C15H10O6, yellow amorphous powder 13 . Luteolin (3), C15H10O6, yellow amorphous powder [14].

Steroids from Mallotus paniculatus

The Mallotus species (Euphorbiaceae) are used in traditional medicine for different ailments ranging from minor infections such as gastrointestinal disorders to dysentery, hepatic diseases, cutaneous diseases, fever and malaria, and a series of other indications [1]. M. paniculatus is distributed in southeastern Asia and China [2]. Previous investigations on the constituents of M. paniculatus have isolated several compounds such as cardenolides, triterpenoids, steroids, flavonoids, and unsatured fatty acids, and the plant extract was found to possess antioxidant and antiradical activities [3–7]. To find further active principles from M. paniculatus, we investigated the plant. M. paniculatus was collected from Xishuangbanna of Yunnan, China in October, 2009. The air-dried stems (12 kg) were chopped and exhaustively extracted with 95% EtOH. Water (1.5 L) was added to the EtOH extract (500 g), and the resulting solution was partitioned with CHCl3, EtOAc, and n-BuOH successively (five times, each 0.8 L). The EtOAc extract (80 g) was separated on a silica gel column, eluting with petroleum ether containing increasing amounts of acetone to get eight fractions. Fraction B (2.2 g) was subjected to repeated column chromatography (silica gel, petroleum ether–acetone 1:0 to 0:1; then Sephadex LH-20, CHCl3–MeOH 3:2) to afford 1 (3.9 mg), 2 (3.4 mg), 4 (9.5 mg), 5 (2.3 mg), 6 (168 mg), and 7 (10 mg). Fraction C (4.1 g) was chromatographed over repeated silica gel (CHCl3–MeOH 1:0 to 0:1; then Sephadex LH-20, MeOH) to afford 3 (40 mg) and 8 (1 g). Compound 1, C29H48O2, white amorphous powder. The ESI mass spectrum exhibited peaks for ions at m/z 429 [M + H]+. The PMR (C5D5N, , ppm, J/Hz) showed characteristics signals of sterols at 0.67 (3H, s, H-18), 0.84 (3H, t, J = 6.5, H-29), 0.87 (3H, d, J = 6.8, H-26), 0.89 (3H, d, J = 6.8, H-27), 0.98 (3H, d, J = 6.5, H-21), 1.12 (3H, s, H-19), 3.86 (1H, m, H-3), and 5.88 (1H, s, H-6). The 13C NMR and DEPT spectra (C5D5N, , ppm) displayed signals at 12.1 (C-18), 12.3 (C-29), 17.3 (C-19), 19.2 (C-26), 19.3 (C-27), 20.0 (C-21), 21.5 (C-11), 23.5 (C-15), 26.5 (C-28), 26.9 (C-23), 29.0 (C-16), 29.6 (C-25), 32.2 (C-2), 34.3 (C-22), 36.3 (C-20), 36.9 (C-1), 38.7 (C-10), 39.1 (C-12), 42.9 (C-4), 43.4 (C-13), 45.6 (C-24), 46.1 (C-8), 50.3 (C-9), 50.6 (C-17), 55.1 (C-14), 70.2 (C-3), 126.0 (C-6), 166.4 (C-5), 201.5 (C-7). By comparison of the spectral data with those reported in the literature, 1 was identified as (24R)-3 -hydroxystigmast-5-en-7-one [8]. Compound 2, C29H46O2, white needles, mp 151–152 C. The ESI mass spectrum exhibited peaks for ions at m/z 427 [M + H]+. By comparison of the spectral data with those reported in the literature, 2 was identified as (24R)-3 -hydroxystigmast5,22-dien-7-one [9]. Compound 3, C28H44O2, white amorphous powder. The mass spectrum exhibited peaks for ions at m/z 412 [M] + (60), 397 (13), 394 (16), 314 (78), 287 (100), 285 (45), and 269 (36). The PMR (C5D5N, , ppm, J/Hz) showed characteristics signals of sterols at 0.68 (3H, s, H-18). 0.85 (3H, d, J = 6.7, H-27), 0.87 (3H, d, J = 7.6, H-26), 0.99 (3H, d, J = 6.4, H-28), 1.08 (3H, d, J = 6.4, H-21), 1.13 (3H, s, H-19), 3.86 (1H, m, H-3), 5.22 (1H, dd, J = 8.7, 8.7, H-22), 5.03 (1H, dd, J = 9.1, 9.1, H-23), 5.88 (1H, s, H-6). The 13C NMR and DEPT spectra (C5D5N, , ppm) displayed signals at 12.2 (C-18), 17.3 (C-19), 19.2 (C-27), 19.3 (C-26), 20.0 (C-11), 21.4 (C-28), 21.7 (C-21), 23.4 (C-15), 29.6 (C-16), 32.2 (C-2), 32.3 (C-26), 36.9 (C-1), 39.1 (C-10), 40.6 (C-12), 40.8 (C-20), 42.8 (C-4), 42.9 (C-24), 45.6 (C-13), 50.2 (C-8), 50.6 (C-9), 51.2 (C-17), 55.1 (C-14), 70.2 (C-3), 125.9 (C-6), 129.6 (C-23), 138.8 (C-22), 166.3 (C-5), 201.4 (C-7). By comparison of the spectral data with those reported in the literature, 3 was identified as 22E,24S-3 -hydroxy-24-methylcholesta-5,22-dien-7-one [10].