Da-Le Guo

Polycyclic Spiro Lignans and Biphenyl Tetrahydrofuranone Lignans from Gymnotheca involucrata

Four rare polycyclic spiro lignans (1-4) and four new biphenyl tetrahydrofuranone lignans (5-8) were isolated from the whole plant of Gymnotheca involucrata. The structures of the new compounds were elucidated on the basis of detailed spectroscopic analysis and the absolute configuration of 1 was confirmed by single crystal X-ray diffraction. Bioassay results showed that compounds 2 and 6 exhibited weak antifungal activity against Uromyces viciae-fabae at 100 ppm in leaf-disc assays, while compound 3 demonstrated moderate insecticidal activity against Diabrotica balteata at 500 ppm in an artificial diet assay.

Three new oxazoline alkaloids from Gymnotheca chinensis

Abstract Three novel oxazoline alkaloids, 1-oxa-3-azaspiro [4.5] dec-2-ene-8-one (1), 1-oxa-3-azaspiro [4.5] dec-2, 6-diene-8-one (2), and 1-oxa-3-azaspiro [4.5] dec-10-methoxy-2, 6-diene-8-one (3) were isolated from the methanol extract of the whole plant of Gymnotheca chinensis. The chemical structures were established by means of spectroscopic analysis including one- and two-dimensional NMR spectroscopy.

Chemical Composition of Alhagi sparsifolia Flowers

Alhagi sparsifolia (Leguminosae) is a perennial herb or semi-bush that is broadly distributed in the flora of Central Asia, i.e., Tajikistan, Kazakhstan, Uzbekistan, Turkmenistan, and Kyrgyzstan [1]. It grows along river banks and in arid zones of the provinces Gansu, Inner Mongolia, and Qinghai and Xinjiang–Uyghur Autonomous Region (XUAR) of China [2]. It is used in traditional Uyghur medicine to treat fever, rheumatism, diarrhea, stomach pain, headache, toothache, and cancer [3]. Flowers are usually used as a tincture for use by local residents. Previously, catechins, proanthocyanidins, coumarins, flavonoids, steroids, and alkaloids were isolated from the plant [4, 5]. Dried flowers (7 kg) were collected in XUAR and extracted by refluxing EtOH (75%) in a flask at 85°C for 3 h. The condensed extract (497.7 g) obtained after solvent distillation was suspended in H2O and worked up sequentially with petroleum ether, EtOAc, and n-BuOH. The EtOAc fraction (57.7 g) was chromatographed over a column of silica gel followed by gradient elution by CH2Cl2–MeOH (1:0 0:1) and purification over a column of Sephadex LH-20 to afford compounds 1–15. The structures of 1–15 were determined using spectral data (1D and 2D NMR and mass spectroscopy) and comparisons of the analyses with those published [6–20]. Genistein (2), isovanillic acid (3), syringetin (4), gentisic acid (10), and genistin (11) were isolated for the first time from the genus Alhagi; heptacosan-1-ol (1) and gallic acid (14) were isolated for the first time from this plant. Heptacosan-1-ol (1), 80.6 mg, white amorphous powder, C27H56O, mp 82–83 C. ESI-MS, m/z: 395.3 [M – H] –. 1Í NMR spectrum (400 MHz, CDCl3, , ppm, J/Hz): 3.64 (3H, t, J = 6.6, H-1), 1.57 (2H, dt, J = 13.7, 6.7, H-2), 1.51–0.96 (48H, m, H-3–26), 0.88 (3H, t, J = 6.7, H-27) [6]. Genistein (2), 14.9 mg, pale-yellow amorphous powder, Cl5Hl0O5, mp 296–298 C. ESI-MS, m/z: 269.7 [M – H] –. 1Í NMR spectrum (400 MHz, CD3OD, , ppm, J/Hz): 8.07 (1H, s, H-2), 7.39 (2H, d, J = 8.6, H-2 , 6 ), 6.86 (2H, d, J = 8.6, H-3 , 5 ), 6.36 (1H, br.s, H-8), 6.24 (1H, br.s, H-6) [7]. Isovanillic acid (3), 3.8 mg, white needle-like crystals, Cl5Hl0O5, mp 296–298 C. ESI-MS, m/z: 269.7 [M – H] –. 1Í NMR spectrum (400 MHz, CD3OD, , ppm, J/Hz): 8.07 (1H, s, H-2), 7.39 (2H, d, J = 8.6, H-2 , 6 ), 6.86 (2H, d, J = 8.6, H-3 , 5 ), 6.36 (1H, br.s, H-8), 6.24 (1H, br.s, H-6) [7]. Syringetin (4), 8.6 mg, pale-yellow amorphous powder, C17H14O8, mp 224–226 C. ESI-MS, m/z: 345.5 [M – H] –. 1Í NMR spectrum (400 MHz, DMSO-d6, , ppm, J/Hz): 12.44 (1H, s, 5-OH), 10.75 (1H, s, 7-OH), 9.47 (1H, s, 3-OH), 9.13 (1H, s, 4 -OH), 7.51 (2H, s, H-2 , 6 ), 6.52 (1H, d, J = 2.0, H-8), 6.20 (1H, d, J = 2.0, H-6), 3.84 (6H, s, 3 , 5 -OCH3) [9]. Isorhamnetin (5), 6.1 mg, yellow amorphous powder, C16H12O7, mp 303–305 C. ESI-MS, m/z: 315.9 [M – H] –. 1Í NMR spectrum (400 MHz, DMSO-d6, , ppm, J/Hz): 12.46 (1H, s, 5-OH), 10.77 (1H, br.s, 7-OH), 9.74 (1H, br.s, 3-OH), 9.12 (1H, br.s, 4 -OH), 7.75 (1H, d, J = 1.8, H-2 ), 7.69 (1H, dd, J = 8.7, 1.8, H-6 ), 6.94 (1H, d, J = 8.7, H-5 ), 6.48 (1H, d, J = 1.7, H-8), 6.19 (1H, d, J = 1.7, H-6), 3.84 (3H, s, 3 -OCH3) [10]. Quercetin (6), 19.7 mg, yellow amorphous powder, C15H10O7, mp 297–299 C. ESI-MS, m/z: 301.5 [M – H] – [11]. Kaempferol (7), 7.3 mg, yellow amorphous powder, C15H10O6, mp 267–269 C. ESI-MS, m/z: 285.5 [M – H] –. 1Í NMR spectrum (400 MHz, DMSO-d6, , ppm, J/Hz): 12.48 (1H, s, 5-OH), 10.78 (1H, s, 7-OH), 10.10 (1H, s, 4 -OH), 9.37

Bioactive Constituents of Ziziphora clinopodioides

Ziziphora clinopodioides Lam. (Labiatae), a medicinal and edible plant, is mainly distributed in Xinjiang of China, Iran, Turkey, Mongolia, and Central Asia. It is commonly used in traditional Uyghur medicine for the treatment of fever, edema, neurasthenic, insomnia, tracheitis, lung abscess, hemorrhoids, hypertension, angina pectoris, coronary artery disease, and other cardiovascular diseases [1–4]. Phytochemical investigations on the genus Ziziphora have mainly focused on essential oil components as well as a few flavonoids, caffeoyl derivatives, fatty acids, phenolic acids, triterpenoids, and sterols [4]. In our previous studies, Z. clinopodioides Lam. was shown to acquire notable antihypertensive, antidiabetic, and antioxidant effects. In order to explore the antihypertensive constituents of this plant, the commonly adopted in vitro model of rat thoracic aortic rings [4] were applied for the bioassay-guided fractionation of active components from Z. clinopodioides Lam., with 11 compounds isolated from the 70% EtOH extract. Based on spectroscopic analyses, their structures were identified as diosmetin (1), apigenin (2), luteolin (3), caffeic acid (4), 5,7,2 -trihydroxyflavone 2 -O-D-glucopyranoside (5), methyl rosmarinate (6), betulinic acid (7), dibutyl phthalate (8), oleanolic acid (9), acacetin (10), and 5,6,4 -trihydroxy-7,8,3 -trimethoxyflavone (thymonin, 11), respectively, among which compounds 7 and 8 were obtained from the genus Ziziphora for the first time. Apigenin (2), luteolin (3), methyl rosmarinate (6), and oleanolic acid (9) were identified as potential vasorelaxant principles. Methyl rosmarinate (6), caffeic acid (4), and luteolin (3) possessed significant antioxidant capacities. Ziziphora clinopodioides along with the active principle oleanolic acid (9) were also reported to possess exciting antidiabetic properties herein for the first time.

Mahimbrine A, a Novel Isoquinoline Alkaloid Bearing a Benzotropolone Moiety from Mahonia imbricata

A novel isoquinoline alkaloid, mahimbrine A, possessing a rare benzotropolone framing scaffold, was isolated from the endemic plant of Mahonia imbricata. Its structure was established on the basis of extensive spectroscopic analysis. A plausible biosynthetic route of mahimbrine A was proposed. Mahimbrine A showed no antimicrobial activity at the concentration of 1 mg/mL.

Chemical Constituents of the Aerial Parts of Schnabelia oligophylla

A new triterpenoid derivative, 2,3-seco-bauer-8-en-2,3-dioic acid (1), a new natural product, 3α-hydroxyolean-13(18)-en-24-oic acid (2), along with 19 known compounds (3–21), were isolated from the methanol extract of the aerial parts of Schnabelia oligophylla. The chemical structures were established by means of spectroscopic analysis including one- and two-dimensional NMR spectroscopy and comparison with previously reported data.