Isolation,characterization, and xanthine oxidase inhibitory activities of flavonoids from the leaves of Perilla frutescens

Abstract

Phytochemical investigation of the water extract from the leaves of Perilla frutescens (Lamiaceae) led to the isolation of a new flavanone, a new chalcone, and a new aurone, namely, (2S)-5,7-dimethoxy-8,4'-dihydroxyflavanone (1), 2',4'-dimethoxy-4,5',6'-trihydroxychalcone (2), and (Z)-4,6-dimethoxy-7,4'-dihydroxyaurone (3), respectively. The structures were unambiguously elucidated on the basis of spectroscopic data. And the absolute configuration of 1 was determined by analysis of electronic circular dichroism spectrum. The isolated compounds were evaluated for their inhibitory effects on xanthine oxidase in vitro. Among them, 2 showed more potent activity than the positive control allopurinol, a well-known XO inhibitor clinically used for treatment of gout. Lineweaver-Burk transformation of the inhibition kinetics data demonstrated that it was a mixed-type inhibitor.

     

Two new C-glycosylflavones from the leaves of Iris lactea var.chinensis

Two new acylated C-glycosylflavones were isolated from the leaves of Iris lactea var. chinensis, and their structures were elucidated on the basis of extensive NMR experiments and mass spectrometry methods and were assigned as 5-hydroxy-4＇- methoxyflavone-7-O-（β-D-2＇＇＇＇4＇＇＇＇-diacetylrhamnopyranosyl）-6-C-[ O-（α-L-6＇＇＇-acetyl-glucpyranosyl）-1→2-β-D-glucopyrano- side] （irislactin A） and 5-hydroxy-4＇,7-dimethoxyflavone-6-C-[O-（α-L-2＇＇＇,3＇＇＇-diacetylrhanmo-pyranosyl）-1→ 2-β-D-glucopyranoside] （irislactin B）.     

Two new compounds from the leaves of Calocedrus microlepic var. formosana

Two new compounds, 15-methoxypinusolidic acid (1) and isonerylgeraniol-18-oic acid (2) together with four knowns taiwaniaflavone (3), nerylgeraniol-18-oic acid (4), 3-(3,4-dihydroxyphenyl)-1-propanol (5), and amentoflavone (6) are isolated from the leaves of Calocedrus microlepic var. formosana. Compounds 1 and 2 were elucidated as labdane diterpene and linear diterpene, respectively, through spectral studies.     

Molecular genetic study on the anthocyanin chemotypes of Perilla frutescens var. crispa

The chemotypes found in various plant species are the good subjects for the studies to understand the regulatory mechanism in secondary metabolism. The biochemistry and molecular biology of flavonoid biosynthesis was studied using chemotypes of Perilla frutescens var. crispa differing anthocyanin accumulation. The expression of the most of structural genes for anthocyanin biosynthesis was coordinately regulated in chemotype-specific manner and by light. However, the genes for shared enzymes between anthocyanin and flavone pathway were expressed both chemotypes. Biochemical characteristics of enzymes involved in anthocyanin biosynthesis were investigated in this plant. Furthermore, the candidates of regulatory factors, members of MYB-bHLH-WD complex, of anthocyanin production were characterized in this plant.     

Two Pairs of 7,7′-Cyclolignan Enantiomers with Anti-Inflammatory Activities from Perilla frutescens

Perilla frutescens (L.) Britt. (Labiatae), a medicinal plant, has been widely used for the therapy of multiple diseases since about 1800 years ago. It has been demonstrated that the extracts of P. frutescens exert significant anti-inflammatory effects. In this research, two pairs of 7,7′-cyclolignan enantiomers, possessing a cyclobutane moiety, (+)/(−)-perfrancin [(+)/(−)-1] and (+)/(−)-magnosalin [(+)/(−)-2], were separated from P. frutescens leaves. The present study achieved the chiral separation and determined the absolute configuration of (±)-1 and (±)-2. Compounds (+)-1 and (−)-1 have notable anti-inflammatory effects by reducing the secretion of pro-inflammatory factors (NO, TNF-α and IL-6) and the expression of pro-inflammatory mediators (iNOS and COX-2). These findings indicate that cyclolignans are effective substances of P. frutescens with anti-inflammatory activity. The present study partially elucidates the mechanisms underlying the effects of P. frutescens.     

Two 3,4-seco-lupane triterpenes from leaves of Acanthopanax divaricatus var. albeofructus

Two 3,4-seco-lupane triterpenoids (1, 2) were isolated from the leaves of Acanthopanax divaricatus var. albeofructus (Araliaceae). Based on the spectroscopic data, the chemical structures of 1 and 2 were characterized as 24-hydroxychiisanogenin and 22alpha-hydroxychiisanogenin, respectively. 1 was a new compound and 2 was isolated for the first time from the natural source, although it had been obtained as an enzymatically hydrolyzed artifact from 22alpha-hydroxychiisanoside.     

Two new diterpenoids from Rabdosia japonica var.glaucocalyx

Two new diterpenoids, named glaucocalyxin F and glaucocalyxin X, respectively, were isolated from the whole plant of Rabdosia japonica （Burm. f.） Hara var. glaucocalyx （Maxim.） Hara. Their structures was established on the basis of spectral analysis.     

白花刺参中两个新三萜皂苷

从著名藏药白花剌参（Morina nepalensis var.alba Hand-Mazz）全草的水溶 性部分中分离得到两个新的乌苏烷型三萜皂苷，命名为剌参苷A(1)和剌参苷B(2). 应用2DNMR新技术，包括^1H-^1H COSY，HSQC，HMBC，2D HMQC-TOCSY，ROESY，以 及选择性激发实验1D SELTOCSY和1D SELNOESY，并结合化学方法，确定它们的结构 分别为3-O-a-L-阿拉伯吡喃糖基-（1→3）-α-L-阿拉伯吡喃糖基坡摸醇酸28-O-β -D-葡萄吡喃基-(1→6) -β-D-葡萄吡喃糖苷（1）和3-O-a-L-阿拉伯吡喃糖基-（ 1→3）-β-D-木糖吡喃基坡摸醇酸28-O-β-D-葡萄吡喃基-(1→6) -β-D-葡萄吡喃 糖苷（2），并对其氢和碳的化学位移进行了全归属。     

Two new alkaloids from Crinum asiaticum var. sinicum

Two new alkaloids (1, 2) were isolated from the whole plants of Crinum asiaticum var. sinicum together with seven known alkaloids. The structures of the new alkaloids were elucidated by spectroscopic analyses and chemical conversions from known alkaloids. New alkaloid 1 was isolated for the first time as a natural product, although it has been prepared as a synthetic product.     

A Novel Atisane Diterpenoid from Spiraea japonica var. acuta

A novel ent‐atisane lactone, spiramilactone E ( 1 ), was isolated from Spiraea japonica var. acuta Yu . Its structure was elucidated by extensive spectroscopic analyses, and unequivocally confirmed by single‐crystal X‐ray diffraction (Fig. 2). Compound 1 contains a γ‐lactone moiety between the 6‐OH function and C(20), and β‐configuration for the 7‐OH group, in contrast to known related diterpenes previously isolated from the S. japonica complex.     

紫苏叶与白苏叶的总黄酮和微量元素的比较分析

为比较分析紫苏叶与白苏叶的总黄酮和微量元素的含量差异,用可见分光光度法测定了两者总黄酮的含量,用电感耦合等离子体原子发射光谱法(ICP-AES法)测定了两者微量元素的含量。结果表明,测得紫苏叶与白苏叶中总黄酮的含量分别为7.49%和5.69%,两者均含有Cu、Mn、Zn、Fe等多种微量元素,但含量存在一定的差异。白苏作为紫苏的同种植物资源,有待进一步的开发和利用。     

Two new steroidal alkaloids from Veratrum nigrum var. ussuriense

<正>Two new steroidal alkaloids,veraussines A(1) and B(2) were isolated from the roots and rhizomes of Veratrum nigrum var.ussuriense.Their structures were determined as N-(ethoxycarbonyl)- 1α,2β,3α,15α-tetrahydroxy-5β-jervanin- 12-en- 11-one(1) andN-(methoxycarbonyl)- 1α,2β,3α,15α-tetrahydroxy-5β-jervanin- 12-en- 11 -one(2) by spectroscopic analysis.     

Two new flavonol glycosides from Sarcopyramis bodinieri var. delicate

Detailed chemical investigation of the herb Sarcopyramis bodinieri var. delicate resulted in the isolation of two new flavonol glycosides, namely, isorhamnetin-3-O-(6'-OE-feruloyl)-beta-D-glucopyranoside (1) and isorhamnetin-3-O-(6'-O-E-feruloyl)-beta-Dgalactopyranoside (2). In addition, four known compounds, quercetin-3-O-(6'-acetyl)-beta-Dglucopyranoside (3), isorhamnetin-3-O-(6'-acetyl)-beta-D-glucopyranoside (4), quercetin-3-O-(6'-O-E-p-coumaroyl)-beta-D-glucopyranoside (5), and isorhamnetin-3-O-(6'-O-E-pcoumaroyl)-beta-D-glucopyranoside (6) were obtained. The structures of the new isolates were determined by extensive spectroscopic analysis.     

Two new xanthons from Garcinia rigida leaves

Two new xanthons, musaxanthone (1) and asmaxanthone (2) were isolated from the leaves of Garciniarigida. The structures were determined by means of spectroscopic analysis.     

Two new chemical constituents from Daphne odora Thunb. var. marginata

Two new phenolic constituents, daphnenone (1) and daphneone (2), were isolated from the stem bark of Daphne odora Thunb. var. marginata. Their structures were established on the basis of spectroscopic analysis. Compounds 1 and 2 were tested for cytotoxic activity by MTT assays on five human tumour cell lines, K562, A549, MCF-7, LOVO and HepG2. Compound 1 showed obvious cytotoxic activity against all the five cell lines.     

DPPH radical scavenging and xanthine oxidase inhibitory activity of Terminalia macroptera leaves

From a methanol extract of the leaves of the Malian medicinal tree Terminalia macroptera, cis-polyisoprene (1), chebulic acid trimethyl ester (2), methyl gallate (3), shikimic acid (4), corilagin (5), rutin (6), narcissin (7), chebulagic acid (8) and chebulinic acid (9), were isolated. Cispolyisoprene (1) was the major non-polar constituent. The novel compound 2 showed high radical scavenging activity (IC50 4.7 microg/mL), but was inactive as xanthine oxidase inhibitor. The major substituent of the crude extract, substance 5, showed a high radical scavenger effect (IC50 2.7 microg/mL) and weak xanthine oxidase inhibition (IC50 ca 105 microg/mL). The antioxidant and radical scavenging effects of some of the substances identified in this study may to some extent explain the medical use of this tree in West Africa.     

ααTwo new eudesmane sesquiterpenes from Lactuca sativa var. anagustata L

Two new eudesmane sesquiterpene lactones were isolated from the stalk of Lactuca sativa var.anagustata L and their structureswere elucidated by means of spectroscopic methods,including 2D NMR(~1H-~1H COSY,HMBC and NOESY) as 1β-O-β-D-glucopyranosyl-4α-hydroxyl-5α,6β,11βH-eudesma-12,6α-olide(1) and 1β-hydroxyl-15-O-(p-methoxyphenylacetyl)-5α,6β,11βH-eudesma-3-en-12,6α-olide(2).     

Two new phenolic glycosides from Viburnum plicatum var. plicatum f. plicatum

Two new glycosides, named dideoxyplicatumoside A (1) and erythro-syringylglycerol-beta-O-4'-(+)-isoeucommin A 4'-O-beta-D-glucopyranoside (2), together with seven known compounds, were isolated from the leaves of Viburnum plicatum Thunb. ex Murray var. plicatum f. plicatum. Their structures were established on the basis of NMR, MS and chemical data.