A Dihydroisocoumarin from the Rhizome of Aloe pulcherrima Negera Abdissa * and Abdulwahid Abamecha Department of Chemistry, College of Natural Sciences, Jimma University, Jimma, Ethiopia * Corresponding author: Abdissa N, Department of Chemistry, College of Natural Sciences, Jimma University, Jimma, Ethiopia, Tel: +251913354086; E-mail: negeraabdisa@gmail.com Received: November 20, 2017; Accepted: December 31, 2017; Published: January 02, 2018 Copyright: © 2018 Abdissa N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Chromatographic separation of the dichloromethane/methanol (1:1) extract of the Aloe pulcherrima rhizome afforded a new dihydroisocoumarin derivative (1) along with six anthraquinone derivatives (2-7). The chemical structures of the compounds were established based on spectroscopic analyses including NMR ( 1 H and 13 C NMR, 1 H- 1 H COSY, HMQC, HMBC, NOESY), MS and comparison with reported literature. The isolated compounds were evaluated for in vitro antibacterial and antiplasmodial activities. Almost all compounds showed antibacterial activity with the highest activity observed for compound 5 against Enterococcus faecalis. Whereas, only compound, 3, 4, 5 and 6 showed antiplasmodial activity against chloroquine-resistant (W2) strain of Plasmodium falciparum. Keywords: Asphodelaceae; Aloe pulcherrima; Rhizome; Dihydroisocoumarin; Anthraquinone; Antibacterial; Antiplasmodial Introduction Te genus Aloe (family Asphodelaceae, subfamily Alooideae) comprises of more than 400 species, ranging from diminutive shrubs to large tree-like mainly distributed in Africa and Madagascar with only a few species found in the Arabian Peninsula [1-3]. Aloe in Ethiopia is represented by 46 species, including 16 endemic species [4,5]. Aloe pulcherrima is one of the endemic species growing in Ethiopia. Te name “ pulcherrima ” derived from “ pulcher ”, refers to the beauty of the plant with bright red fowers and blue-like green leaves [5]. It has been traditionally used for the treatments of various ailments, particularly for wound healing, constipation and as insect repellents [6,7]. Te phytochemical analysis of the leaf latex [7] and the roots of A. pulcherrima have resulted in the isolation of anthraquinones and pre-anthraquinones which have been reported to have antibacterial [7,8], antifungal [7] and antiplasmodial [8]. As part of our on-going program in search for new bioactive natural compounds from African traditional medicinal plants [8,9], now we report the isolation of one new compound (1) and six known compounds (2-7) along with their antibacterial and antiplasmodial activities from the rhizome of A. pulcherrima . Materials and Methods General Column chromatography was carried out on silica gel (0.06-0.2 mm). Gel fltration was performed on Sephadex LH-20. Analytical TLC was performed on Merck pre-coated silica gel 60 F 254 plates. Melting points were measured on B-540 melting point apparatus. UV spectra were recorded on a UV-3100 PC spectrophotometer (UWR international, Shanghai, China). IR spectra were recorded on a Nicolet 380 FT-IR spectrometer (Termo Electron Corporation, Madison, WI, USA). High Resolution ESI-MS was done on a Micromass AC-TOF micro mass spectrometer (Micro mass, Agilent Technologies 1200 series, Tokyo, Japan). Optical rotations were measured on a P-1020 polarimeter. 1D ( 1 H, 13 C) NMR and 2D (COSY, HSQC, HMBC, NOESY) NMR spectra were recorded on an Avance 500 MHz spectrometer at 500 MHz ( 1 H) and 125 MHz ( 13 C) at 298 K using the residual solvent peaks as a reference. Plant material Te rhizome of A. pulcherrima was collected from Guddo, Seka District, Jimma zone, Oromia regional state, Ethiopia in September 2016. Te plant material was identifed and the voucher specimen (voucher number AP001/2015) has been deposited in Jimma University Herbarium. Extraction and isolation Te air-dried rhizome (320 g) of A. pulcherrima was milled into powder and then extracted using CH 2 Cl 2 /MeOH (1:1) four times for 24 hrs at room temperature. Te extract was concentrated under vacuum using rotary evaporator to yield a dark brown residue (23 g, 7.2%). A 20 g portion of the extract was subjected to column chromatography on silica gel (300 g) eluting with petroleum ether containing increasing amount of ethyl acetate to aford 24 major fractions ca. 250 mL each. Fractions 2-10 (5% EtOAc in petroleum ether) were combined and purifed by Sephadex LH-20 (eluting with CH 2 Cl 2 /MeOH; 1:1) to give chrysophanol (2, 3.8 mg) and aloesaponarin II (3, 4.2 mg). Fractions 11-17 (10% ethyl acetate in petroleum ether) showed mixtures of four compounds, which were combined and subjected to column chromatography (column size: 80 cm length and 4 cm diameter) on silica gel (250 g; eluent: increasing gradient of ethyl acetate in petroleum ether) followed by Sephadex LH-20 (eluting with CH 2 Cl 2 /MeOH; 1:1) yielding compound 1 (2.7 mg), aloesaponarin I (4, 3.1 mg), laccaic acid D-methyl ester (5, 3.6 mg) and aloesaponol I (6, 2.9 mg); while fractions 18-22 (20% EtOAc in petroleum ether) showed colourless blue fuorescing precipitate that was washed with 100% petroleum ether and further purifed on Sephadex LH-20 (eluting with CH 2 Cl 2 /MeOH; 1:1) to give aloesaponol II (7, 4.3 mg). N a t u r a l P r o d u c t s C h e m i s t r y & R e s e a r c h ISSN: 2329-6836 Natural Products Chemistry & Research Abdissa and Abamecha, Nat Prod Chem Res 2018, 6:1 DOI: 10.4172/2329-6836.1000301 Research Article Open Access Nat Prod Chem Res, an open access journal ISSN: 2329-6836 Volume 6 • Issue 1 • 1000301