2
R. C. FORESTRANIA ET AL.
1. Introduction
Garcinia is a plant genus of more than 300 species that belongs to the Family
Clusiaceae (Hemshekhar et al. 2011; Koranappallil 2017). It is largely distributed in
tropical and humid regions, such as Africa, Asia, Australia, and Polynesia (Chandran
1996; Lathifah et al. 2010; Hemshekhar et al. 2011). G. daedalanthera is originated from
Sulawesi Island and also found in other rain forests in Indonesia (Najib et al. 2017). A
recent in vivo study in rats observed an antihyperlipidemic activity of an ethanolic
extract of G. daedalanthera leaves (Najib et al. 2018). Phytochemical screening
identified the following classes of compounds, sterols, saponins, alkaloids, and other
phenolic compounds (Najib et al. 2017). In a cancer-related research, the benzophe-
none garciniagifolone isolated from G. preussi was found to show cytotoxicity against
human HT-29 colon and DU-145 prostate cancer cell lines (Biloa Messi et al. 2014).
However, isolation of phytochemical constituents from G. daedalanthera and biological
activities on cancer therapy or prevention have not been reported. Therefore,
this study focus on isolation and biological evaluation of secondary metabolites
from G. daedalanthera.
Ten compounds were elucidated using 1 D- and 2 D-NMR, LC-MS and GC-MS, IR,
polarimetry, and UV-visible physical spectroscopic methods. Two new glycerol esters,
(S)-2-hydroxy-3-(octanoyloxy)propyl tetracosanoate (1) and (S)-3-(((S)-11-acetoxyoctade-
canoyl)oxy)propane-1,2-diyl diacetate (2) were structurally elucidated. Also, eight
known compounds were identified. Cytotoxicity and the potential against reactive
oxygen species (ROS) of all isolates were evaluated.
2. Results and discussion
Compound 1 was isolated as white solid. Its molecular formula assigned C35H68O5 was
deduced by HRESIMS m/z 591.4973 [M þ Na]þ (calcd for the sodiated ion C35H68O5Na
at 591.4959). ESIMS fragmentation at m/z 485.8124 was formed via McLafferty
rearrangement due to fragmentation of a fatty acid ester (Figure S7) (Fagerquist et al.
1999). A common mass fragment of a fatty acid ester was observed at m/z 443.2234.
IR showed ꢀmax bands at 3383 cmꢀ1 for hydroxyl group, at 1732 cmꢀ1 for carbonyl
ester, and at 2849 and 2917 cmꢀ1 alkane groups. 1H NMR and 13C NMR data
(Table S2) included two methyls (dH 0.86, t, H-24/80), thirty methylene (dH 2.32, t,
H-2/20; 1.60, m, H-3/30; 1.23, m, H-(4-23)/H-40/50; 1.24, m, H-60; 1.26, m, H-70; 4.15, m,
H-100/300), a methine (dH 4.09, m, H-200), and two carbonyl carbons (dC 174.16, C-1/10).
1
The molecule substitution pattern was established based on H-1H COSY correlations
from H-2 to H-3. HMBC correlations from H-100 to C-1, H-100 to C-200, and H-300 to C-100
indicated the presence of a glyceryl group attached to a carbonyl group of a fatty
acid ester. The presence of fatty acid diesters (octanoic and tetracosanoic acid esters)
attached to the glycerol group at C-300 and C-100 were derived via COSY (H-24 to H-23,
H-3 to H-2, H-80 to H-70, H-30 to H2’, H-30 to H-40) and HMBC (H-24 to C-22, H-24 to
C-23, H-23 to C-21, H-22 to C-23, H-22 to C-20, H-21 to C-19, H-6 to C-4, H-3 to C-5, H-
2 to C-4, H-3 to C-1, H-80 to C-60, H-60 to C-40, H-30 to C-10, H-20 to C-40, H-20 to C-10)
correlations. Lengths of fatty ester chains were confirmed by a hydrolysis reaction.
Analysis of fatty acid hydrolysis using EIGC-MS positive-ion mode identified fragment