New Labdane-Type Diterpenoids from Leonurus heterophyllus SW.

Abstract

In Vietnamese traditional medicine, the plant Leonurus heterophyllus SW. is known as Ich mau thao, Sung uy, or Choi den. The dried aerial parts of L. heterophyllus (Herba Leonuri) are applicable in the treatment of menstrual pain and child birth, as well as high blood pressure, blood stasis, heart disorders, and dysentery. The dried ripe fruits (Fructus Leonuri) are used to treat edema and as a diuretic.1) Several prefuranic and furanic labdane-type diterpenoids were isolated in previous studies on L. heterophyllus collected in Guangdong province, China.2,3) It is well known that the chemical composition of plants is geographically varied, and the reason for that may be related to the ability of each species to cope with its habitat environment. Therefore we carried out systematic extraction and isolation of the L. heterophyllus species grown in Vietnam, which led to the structure determination of nine labdane-type diterpenoids, including five new compounds, designated leoheteronins A-E (5-9), two phytosterols as a mixture of b-sitosterol and stigmasterol, and the flavone genkwanin (10). The structures of the known diterpenoids hispanone (1), leoheterin (2), hispanolone (3), and galeopsin (4), and 10 were determined by comparing their physical ([a] D ) and spectroscopic data with the literature values.3-6) Compounds 2-4 were among the previous isolates from L. heterophyllus, 1 was isolated from Ballota species (Lamiaceae) 4) but for the first time from a Leonurus species, and 10 is considered to be a chemotaxonomic marker of the genus Leonurus.7) This paper deals with the structure elucidation of the five new labdane-type diterpenoids 5-9. Results and DiscussionThe extraction of the dried aerial parts of L. heterophyllus with MeOH and sequential fractionation using solvents of increasing polarity gave n-hexane-, ethyl acetate-, and 1-BuOHsoluble fractions. Separation of the n-hexane-soluble fraction with silica (Si) gel open-column chromatography, octadecyl Si (ODS) gel open-column chromatography, and repeated preparative ODS HPLC led to the isolation of compounds 1-10 together with a mixture of b-sitosterol and stigmasterol.Leoheteronin A (5) C-16)], six methylene and one methine groups, and two quaternary carbons. Analysis of the data suggested the structure of 5 to be 15,16-epoxylabda-8,13-diene-7,15-dione, which was confirmed on comparison of the NMR data with those of the related compound leopersin G. (Table 1) and 13 C-NMR (Table 2) (Table 1) and 13 C-NMR (Table 2) spectroscopic data showed that 7 was closely related to 5, and the presence of an additional hydroxyl group was deduced from the mass unit of 7. Five new natural labdane-type diterpenoids (5-9), designated leoheteronins A-E, together with four known diterpenoids (1-4), two phytosterols as a mixture of b b-sitosterol and stigmasterol, and the flavone genkwanin (10) were isolated from the aerial parts of Leonurus heterophyllus SW. (Lamiaceae) collected in northern Vietnam. Compound 1 was isolated for the first time from a Leonurus species, an...

Steroids from the aerial parts of Leonurus japonicus

“…Previous investigations on L. japonicus have led to the isolation of many terpenoids and aromatic compounds (Li et al, 2012;Moon, 2010;Romero-González et al, 2006;Seo et al, 2010;Xiong et al, 2015;Zhou et al, 2013). However, only a few steroids have been reported from the genus Leonurus before (Giang et al, 2005;Ye et al, 2014). The present phytochemical examination of the ethanolic extract of L. japonicus has resulted in the characterization of two new (1-2) and 10 known (3-12) steroids (Fig.…”

A Bicyclic Diterpenoid with a New 15,16-Dinorlabdane Carbon Skeleton from Leonurus japonicus and Its Coagulant Bioactivity

“…Previous phytochemical investigations on L . japonicus have led to the isolation of more than 35 labdane diterpenoids [4,9,11,12,13,14,15,16,17]. In the present study, two labdane diterpenoids 1 – 2 and three ergosterols 3 – 5 were obtained from the EtOAc soluble fraction of the EtOH extract of L. japonicus .…”

Synthetic transformations of higher terpenoids. XXVII.* Synthesis of 7-hydroxylabdanoids and their transformations

“…7-Keto-and 7-hydroxyfurolabdanoids showed antibacterial [3], antifeedant [4], and cytotoxic activity [5]. The isolation of 8,9-secofuranolabdanoids that exhibited cytotoxicity against human tumor cells was reported [6].…”

“…The deviations of N(2) and C-1 from the plane of the double bond were 0.686(5) and 1.158(5) A° . The two independent molecules in the crystal formed pairs through two H-bonds N(2)-H…O (5) and N(22)-H…O(1) with parameters H…O 2.08 and 2.10, N…O 2.947(4) and 2.819(4) A° and N-H…O 169 and 138°. The EtOH solvate molecule was also bonded to these pairs through an H-bond O1…O1W 2.722(5) A° .…”