Wan Zuraida Wan Mohd Zain^1,2,3*, Norizan Ahmat^3,4, Yaya Rukayadi⁵, Che Puteh Osman^3,4,

Nor Asma Husna Yusoff⁵, Neneng Winda⁶

¹Faculty of Plantation and Agrotechnology, Universiti Teknologi MARA, Jasin Campus, 77300 Merlimau, Melaka, Malaysia

²Faculty of Plantation and Agrotechnology, Universiti Teknologi MARA, Shah Alam Campus, 40450, Shah Alam, Selangor, Malaysia

³Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia

⁴Atta-ur-Rahman Institute for Natural Product Discovery, Universiti Teknologi MARA Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor, Malaysia

⁵Faculty of Food Science and Technology and Laboratory of Natural Products, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia

⁶Department of Science Education, Faculty of Tarbiyah and Education, Sunan Gunung Djati State Islamic University, Bandung, Indonesia

Abstract

This paper will discuss, in vitro investigation of chemical constituents extracted from the stem bark of Dipterocarpus verrucosus, Dipterocarpus crinitus and Dipterocarpus cornutus against opportunistic filamentous fungi. In this research, 17 compounds comprised of twelve oligostilbenoids, (-)-e-viniferin ,(-)-laevifonol,  (-)-hopeaphenol , (-)-isohopeaphenol, vaticanol B,  diptoindonesin E, hemsleyanol D, davidiol A, resveratrol, ampelopsin A, ampelopsin F, together with three other phenolic; gallic acid derivative, (-)-bergenin, scopoletin and 4-methoxygallocathecin and also two terpene; β-sitosterol and β-sitosterol glucoside have been isolated. In this study, the crude extracts and isolated compounds were evaluated regarding to their antifungal activity; in terms of MIC, MFC and germination assay against pathogenic fungi strains, namely Aspergillus flavus (AF), Aspergillus oligosporus (AO), Rhizophus oryzae (RO) and Fusarium oxysporum (FO) using Clinical and Laboratory Standard Institute (CLSI) methods.  The MIC of crude extracts and isolated compounds against all fungi ranged from 3.8 – 500 µg/mL. F. oxysporum shows the most sensitive microorganisms on crude extract: D. verrucosus, D. cornutus and isolated compound: ε-viniferin with MIC of 3.8 µg/mL. The MIC was lower compared to amphotericin B (4 µg/ml). The strain was killed at the MFC of 31.3, 31.3 and 15.6 µg/mL respectively, as compared to amphotericin B (8 µg/mL). Compounds: resveratrol, laevifonol, ε-viniferin, ampelopsin F, vaticanol B, vaticanol A, isomer of hopeaphenol and isohopeaphenol, β-sitosterol and β-sitosterolglucoside possessed an inhibitory activity on the conidial germination of  F. oxysporum at the concentration of 4× MIC. On top of that, D. cornutus, ampelopsin A and hemsleyanol D possessed a complete sterility at the concentration of 2×MIC while D.verrucosus achieved its inhibitory activity at 1× MIC. To the best of our study, there is no data discussing the inhibition of conidial germination of filamentous fungi using the tested compounds and crudes tested.

Keywords: Antifungal, In vitro, Opportunistic fungi, Phenolic compounds, Stilbenoid