Leucas mollissima, a Source of Bioactive Compounds with Antimalarial and Antimycobacterium Activities

Abstract

A phytochemical investigation of the acetone extract from the aerial parts of Leucas mollissima afforded one new (−)epi-marmelo lactone, (2 S, 4R, 6 S)-2,6-dimethyl-6 hydroxy-7-ene-4-olide (1), along with five known compounds, schensianol A (2), vanillin (3), β-hydroxy propiovanillone (4), lanost-9(11),25-diene-3β,24β-diol (5), and lanost-9(11),23E(24)-diene-3β,25-diol (6). Similarly, an investigation of the methanol extract of the aerial parts of L. mollissima resulted in the isolation of three known compounds, (+)-syringaresinol (7), anisofolin A (8), and apigenin 7-O-β-D(− 6′′-p-E-coumaroyl)-glucoside (9). Structure elucidation of the isolated compounds was carried out using detailed analysis of 1D and 2D nuclear magnetic resonance. All compounds were evaluated for antimalarial activity against Plasmodium falciparum (3D7) and for antimycobacterium activity against Mycobacterium tuberculosis H37Ra and Mycobacterium bovis. Compound 8 was found to have promising antimalarial activity (IC₅₀ 4.39 ± 0.25 µM), promising antimycobacterium activity [IC₅₀ 4.50 ± 0.75 µM (3.31 µg/mL)] against M. tuberculosis H37Ra and at 100 µg/mL, showed 55.6 % inhibition of M. bovis. Compound 9 showed moderate inhibition of P. falciparum growth (35 % inhibition at 10 µM) with respect to the positive control atovaquone and 67.4 % inhibition against M. bovis at 100 µg/mL with respect to the positive control rifampicin.

Key words

Leucas mollissima - Lamiaceae - antimalarial - antimycobacterium - phytochemicals

• References

• 1 Chouhan HS, Singh SK. A review of plants of genus Leucas . J Pharmacogn Phytother 2011; 3: 13-26
• 2 Khanam M, Hassan MA. A critical study of the genus Leucas R. Br. (Lamiaceae) from Bangladesh. Bangl J Plant Taxon 2005; 12: 1-10
• 3 Singh NP, Lakshminarasimhan P, Karthikeyan S, Prasanna PV. Flora of Maharashtra State. Calcutta: Botanical Survey of India; 2001: 734
• 4 Thacker MS, Lala SR, Krishnan MS, Prashad B, Chopra RN, Santapau H, Sastri BN. The wealth of India, raw materials, Vol. VI. New Delhi: CSIR; 1962: 80
• 5 Das SN, Patro VJ, Dinda SC. A review: Ethnobotanical survey of genus Leucas . Pharmacogn Rev 2012; 6: 100-106
• 6 Nishida Y, Konno M, Fukushima Y, Ohrui H, Meguro H. ¹³ C-NMR Studies on Marmelo Lactones and Related 2, 4-di Alkylated γ–lactones. Agric Biol Chem 1986; 50: 191-193
• 7 Zheng XK, Guo JH, Feng WS, Li HW. Three new sesquiterpenes from Euonymus schensianus Maxim. Chinese Chem Lett 2009; 20: 952-954
• 8 Mukonyi KW, Ndiege IO. 2-Hydroxy-4-methoxybenzaldehyde: aromatic taste modifying compound from Mondia whytei skeels. Bull Chem Soc Ethiop 2001; 15: 137-141
• 9 Lou JR, Jiang HE, Zhao YX, Zhao J, Qian JF. Components of the heartwood of from an ancient tomb. Chem Nat Compd 2008; 44: 6-9
• 10 Wang XX, Jia ZJ. Two new lanostane-type triterpenoids from Mulgedium tataricum . Chinese Chem Lett 2006; 17: 204-206
• 11 Wang XX, Lin CJ, Jia ZJ. Triterpenoids and sesquiterpenes from Mulgedium tataricum . Planta Med 2006; 72: 764-767
• 12 Park HB, Lee KH, Kim KH, Lee IK, Noh HJ, Choe SU, Lee KR. Lignans from the root of Berberis amurensis . Nat Prod Sci 2009; 15: 17-21
• 13 Miyaichi Y, Segawa A, Tomimori T. Studies on Nepalese crude drugs. XXIX. Chemical constituents of Dronapuspi, the whole herb of Leucas cephalotes Spreng. Chem Pharm Bull (Tokyo) 2006; 54: 1370-1379
• 14 Rao LJM, Kumari GNK, Rao NSP. Anisofolin-A, a new acylated flavone glucoside from Anisomeles ovata R. Br. Heterocycles 1982; 19: 1655-1661
• 15 Karioti A, Protopappa A, Megoulas N, Skaltsa H. Identification of tyrosinase inhibitors from Marrubium velutinum and Marrubium cylleneum . Bioorg Med Chem 2007; 15: 2708-2714
• 16 Delazar A, Celik S, Gokturk RS, Unal O, Nahar L, Sarker SD. Two acylated flavonoid glycosides from Stachys bombycina, and their free radical scavenging activity. Pharmazie 2005; 60: 878-880
• 17 Ku CT, Chen SC, Wang JP, Wu JB, Kuo SC. Studies on anti-inflammatory constituents of Leucas Mollissima WALL. var. Chinensis Benth. Chin Pharm J 2000; 52: 261-273
• 18 Radfar A, Mendez D, Moneriz C, Linares M, Marin-Garcia P, Puyet A, Diez A, Bautista JM. Synchronous culture of Plasmodium falciparum at high parasitemia levels. Nat Protoc 2009; 4: 1899-1915
• 19 Dzoyem JP, Guru SK, Pieme CA, Kuete V, Sharma A, Khan IA, Saxena AK, Vishwakarma RA. Cytotoxic and antimicrobial activity of selected Cameroonian edible plants. BMC Complement Altern Med 2013; 13: 78-83
• 20 Singh U, Sarkar D. A novel screening method based on menadione mediated rapid reduction of tetrazolium salt for testing of anti-mycobacterial agents. J Microbiol Meth 2011; 84: 202-207
• 21 Khan A, Sarkar D. A simple whole cell based high throughput screening protocol using Mycobacterium bovis BCG for inhibitors against dormant and active tubercle bacilli. J Microbiol Meth 2008; 73: 62-68