Emelina H. Mandia

Secondary metabolites from Tectona philippinensis

The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal plant, afforded 5-hydroxy-3,7,4′-trimethoxyflavone (1), 5,4′-dihydroxy-3,7-dimethoxyflavone (2), squalene (3), a mixture of lupeol (4a) and β-amyrin (4b), chlorophyllide a (5), and hydrocarbons. Antimicrobial tests on 1 and 2 indicated low antifungal activity against the fungi, Candida albicans and Trichophyton mentagrophytes. Compound 1 was also found to have low antibacterial activity against Escherichia coli and Pseudomonas aeruginosa.

Chemical Constituents of Ficus linearifolia and Ficus triangularis

Ficus linearifolia Elmer is an endemic Philippine fig tree distributed in the forests of Luzon, Negros, and Leyte at altitudes up to 900 m above sea level [1]. It was earlier considered as a mere variety of Ficus botryocarpa Miq. [2]. This fig tree was first described in 1907 as an erect tree that reaches a height of 20 m and bears linear lanceolate leaves that are more or less scattered but usually confined towards ends of the branchlets. It grows in low damp wooded ground or along streams in deep ravines at the base of Mt. Banahao (Lucban, Luzon Island) at 750 m above sea level [3]. This fig tree is locally known in the Philippines as daing-daing [4]. Ficus triangularis, commonly known as triangular fig and sweetheart tree, is a native to tropical Africa. It was recently introduced in the Philippines as an ornamental tree [5]. This study was conducted as part of our research on the chemical constituents of the genus Ficus. We earlier reported the isolation of a new neohopane [6] from Ficus pumila. We also reported the isolation of terpenoids and sterols from the endemic Philippine trees, Ficus pseudopalma and Ficus ulmifolia [7]. Recently, we reported the isolation of terpenoids and sterols from another endemic Philippine tree, Ficus odorata. -Sitosteryl-3 -glucopyranoside-6-O-palmitate from the leaves of F. odorata exhibited cytotoxicity against human stomach adenocarcinoma cell line (AGS) with 60.28% growth inhibition [8]. There are no reported chemical constituents and biological activities of F. linearifolia and F. triangularis. We report herein the isolation and structure elucidation of 1–9 from the dichloromethane extract of the air-dried leaves of Ficus linearifolia and 4–13 from the leaves of F. triangularis. To the best of our knowledge, this is the first report on the isolation of these compounds from these trees. Silica gel chromatography of the dichloromethane extract of the leaves of F. linearifolia afforded 1–9. The structure of 1 was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by comparison of their 13C NMR data with those of 11 ,12 -epoxyurs-14-en-3 -yl acetate [9]. The structures of 2–9 were identified by comparison of their 13C NMR data with those reported in the literature for -amyrin (2) [10], -amyrin (3) [10], squalene (4) [11], -sitosterol (5) [12], -stigmasterol (6) [12], polyprenol (7) [13], linoleic acid (8) [14], lutein (9) [15]. The leaves of Ficus linearifolia were collected from the foot of Mt. Banahaw, at around 600 m above sea level (masl), at Avila s Farm, Brgy Palola, Lucban, Quezon, Philippines in March 2012. Voucher specimens were authenticated by Danilo N. Tandang of Philippine National Museum. The air-dried leaves (310 g) of F. linearifolia were soaked in CH2Cl2 for 3 days and then filtered. The filtrate was concentrated under vacuum to afford the crude extract (6 g), which was chromatographed in increasing proportions of acetone in CH2Cl2 at 10% increments by volume as eluents. The CH2Cl2 fraction was rechromatographed (4 ) in petroleum ether to afford 4 (8 mg). The 10% acetone in CH2Cl2 fraction from the chromatography of the crude extract was rechromatographed (3 ) in 7.5% EtOAc in petroleum ether to afford 1 (12 mg). The 20% acetone in CH2Cl2 fraction from the chromatography of the crude extract was rechromatographed (4 ) in 10% EtOAc in petroleum ether to afford 7 (10 mg). The 30% acetone in CH2Cl2 fraction was rechromatographed (3 ) in 15% EtOAc in petroleum ether to afford 8 (15 mg) and a mixture of 2 and 3 (9 mg).

Chromomoric Acid Derivatives from Tectona philippinensis

The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal tree, afforded four new chromomoric acid derivatives ( 1, 2, 3a, and 3b). Their structures were elucidated by extensive 1D and 2D NMR spectroscopy. Antimicrobial testing was carried out on 1- 3 against a panel of bacteria and fungi.

A new triterpene from Glinus oppositifolius

Abstract Aim To investigate the chemical constituents of Glinus oppositifolius. Methods The compounds were isolated by silica gel chromatography. The structure of the new triterpene was elucidated by extensive 1D and 2D NMR spectroscopy. Results The dichloromethane extract of the air-dried leaves of Glinus oppositifolius afforded a new triterpene, oppositifolone ( 1 ), spinasterol ( 2 ), squalene ( 3 ) and lutein ( 4 ). The structure of 1 was elucidated by NMR spectroscopy, while 2 - 4 were identified by comparison of their 13 C NMR data with those reported in the literature. Conclusion A new triterpene was isolated from G. oppositifolius .

Phenolics from Knema stellata subsp. cryptocaryoides

Ten out of the 75 known Malesian species of Knema (Family Myristicaceae) occur in the Philippines [1, 2]. Of these, seven taxa are endemic to the country, mostly occurring in the island of Luzon [1]. Among these taxa is Knema stellata subsp. cryptocaryoides (Elmer) W. J. de Wilde, locally known as durogo. It is a medium-size dioecious tree growing in the lowland forests of Luzon, Sibuyan, and Mindanao. Its wood is locally used for light construction, plywood production, wall paneling, making matchboxes, splints, crates, and wooden patterns, and in the manufacture of wrapping and writing papers [3]. Interestingly, its seeds contain oil that locals use for illumination purposes [3]. Like all other endemic Philippine Knema, this particular subspecies has not been the subject of any chemical study. This study is part of our research on the chemical constituents of trees endemic to the Philippines. We earlier reported the chemical constituents of Cinnamomum utile [4], C. griffithii [5], C. rupestre, C. nanophyllum [6], C. trichophyllum [7], Ardisia squamulosa [8], Ficus linearifolia and F. triangularis [9], F. pseudopalma and F. ulmifolia [10], and F. odorata [11]. We report herein the isolation and structure elucidation of mixtures of 2-[(Z)-heptadec-8-enyl]-6-hydroxybenzoic acid (1a) and 2-[(Z)-pentadec-8-enyl]-6-hydroxybenzoic acid (1b); 3-(heptadec-8-enyl)phenol (2a), 3-(pentadec-8-enyl)phenol (2b), and 3-pentadecylphenol (2c); and saturated long-chain 4-hydroxycinnamate fatty acid esters (3) and -stigmasterol (4) from Knema stellata subsp. cryptocaryoides. This is the first report on the isolation of these compounds from Knema stellata subsp. cryptocaryoides. Samples of Knema stellata subsp. cryptocaryoides were collected from a private farm in Sitio Usiwan, Barangay Palola, Lucban, Quezon in March 2012 by Maryl V. Arceta and Leah D. J. Madrazo of the Southern Luzon State University (SLSU) in Lucban, Quezon. Within this private farm is a patch of secondary forest at 620 m asl, which interestingly harbors a number of endemic species. Voucher specimens were collected and identified by one of the authors (EHM) with collection #903 and deposited at De La Salle University, Manila. The air-dried leaves (330 g) of Knema stellata subsp. cryptocaryoides were ground in a blender, soaked in CH2Cl2 for 3 days, and then filtered. The air-dried stems (255 g) were chopped into small pieces, soaked in CH2Cl2 for 3 days, and then filtered. The filtrates were concentrated under vacuum to afford the crude extracts: 12 g (leaves) and 8 g (stems). The crude extracts were fractionated by silica gel chromatography using increasing proportions of acetone in CH2Cl2 (10% increment) as eluents.

CHEMICAL CONSTITUENTS OF Palaquium luzoniense

1) Chemistry Department and Center for Natural Sciences and Ecological Research, De La Salle University, 2401 Taft Avenue, Manila 1004, Philippines, fax: (+0632) 5360230, e-mail: consolacion.ragasa@dlsu.edu.ph 2) Southern Luzon State University, Lucban, Quezon, Philippines 3) Biology Department and Center for Natural Sciences and Ecological Research,De La Salle University-Manila, Manila, Philippines 4) National Research Institute of Chinese Medicine, 155-1, Li-Nong St., Sec. 2, Taipei 112, Taiwan

CHEMICAL CONSTITUENTS OF Weinmannia luzoniensis

1) Chemistry Department and Center for Natural Sciences and Ecological Research, De La Salle University, 2401 Taft Avenue, Manila 1004, Philippines, fax: (+0632) 5360230, e-mail: consolacion.ragasa@dlsu.edu.ph 2) Southern Luzon State University, Lucban, Quezon, Philippines 3) Biology Department and Center for Natural Sciences and Ecological Research, De La Salle University-Manila, Manila, Philippines, 4) National Research Institute of Chinese Medicine, 155-1, Li-Nong St., Sec. 2, Taipei 112, Taiwan

A New Triterpene from Atalantia retusa Merr.

Atalantia retusa Merr. is a rare Philippine endemic shrub which was reported to exhibit high antinociceptive and anti-inflammatory activities. The dichloromethane extract of the air-dried leaves of A. retusa afforded a new triterpene, retusenol (1), and friedelin (2), dischidiol (3), 5,7-dimethoxy-8- (3-methyl-2-oxybutyl)coumarin (4), humulene (5), and β-caryophyllene (6). The structures of 1 - 4 were elucidated by extensive 1D and 2D NMR experiments. Friedelin, a known analgesic and antiinflammatory drug, is an active principle of the shrub. Compounds 1 - 4 were tested for cytotoxicity against the human cancer lung adenocarcinoma A549, colon carcinoma HCT116 and the non-cancer Chinese hamster ovary AA8 using the MTT assay. Triterpenes 1 - 3 had no linear interpolation with HCT 116 and A549, thus the IC50 value could not be computed. This implied that these compounds did not exhibit any cytotoxic effect against these cell lines. Meanwhile, 4 exhibited moderate cytoxicity against A549, HCT 116 and AA8 with IC50 values of 47.5634, 42.4338 and 46:2751 μ g mL-1, respectively. Compounds 1, 2 and 4 were tested for their antimicrobial properties against seven microorganisms and exhibited the highest activity against B. subtilis, even surpassing the activity of the standard antibiotic Chloramphenicol. They also exhibited antimicrobial activities against P. aeruginosa, S. aureus, C. albicans, and T. mentagrophytes, but were inactive against A. niger and E. coli. Graphical Abstract A New Triterpene from Atalantia retusa Merr.

Anti-nociceptive and anti-inflammatory activities of Atalantia retusa Merr.

Atalantia retusa is an endemic medicinal plant used in the Philippines. Hexane extract from leaves were orally administered on rats and mice and tested using rat paw edema, formalin and writhing assays. Increased pain tolerance was observed in animals administered with the median dose (1.43 mg/Kg BW) in both somatic (P<0.05) and visceral (P<0.01) models by 6.05% and 55.48% better compared to the positive control. The degree of swelling was also reduced by the administration of 1.43 mg/Kg BW at 0.5 to 3.0h after carrageenan injection suggesting a high impact analgesic and anti-inflammatory effects of A. retusa hexane extract.