Biological Activity Evaluation and In Silico Studies of Polyprenylated Benzophenones from Garcinia celebica

Polyprenylated Benzoylphloroglucinols Isolated from Garcinia Species and Their Cytotoxic Effects on Cancer Cell Lines

Polyprenylated benzoylphloroglucinols (PPBPs) make up a group of complex natural products with anticancer potentials that are mainly distributed in Garcinia plants. As part of our intensive exploration on new bioactive substances from this genus, we report two undescribed PPBPs, picrorhizones I (1) and J (2), along with four known analogues (3-6) from the stem bark of Garcinia picrorhiza and Garcinia gracilis. The new structures were elucidated on the basis of spectroscopic analysis, particularly 1D and 2D NMR and HRESIMS, whereas the absolute configurations were determined by a combination of ECD and NMR calculations coupled with a DP4+ probability analysis. Being the least class in genus Garcinia, picrorhizone I possesses a type-A structure with the position of a benzoyl moiety attaching to one of the bridgehead carbons of a bicyclo[3.3.1]nonane skeleton, which differs from its major type-B counterparts. This work also represents the first report on the occurrence of PPBPs in G. gracilis. The cytotoxic evaluation of the isolated compounds revealed that isogarcinol (4) and garciyunnanin L (5) significantly inhibited the growth of KB and Hela S3 cancer cells with IC50 values lower than 10 μM, while 5 was also strongly active against the Hep G2 cancer cell line with an IC50 value of 8.02 μM. Among the B-class derivatives bearing a lavandulyl side chain, cyclization of the moiety in the bicyclic phloroglucinol skeleton enhanced the cytotoxic properties on cancer cells.

A new biphenyl from the stem bark of Garcinia macrantha A.C.Sm

In our continuation of exploring antidiabetic agents from Garcinia species, we found that the methanolic extract of G. macrantha A.C.Sm. exhibited considerable α-glucosidase inhibition of 58.20 ± 0.37% in sucrose substrate and 39.86 ± 2.07% in maltose substrate at 100 μg/mL. Phytochemical investigation on the extract revealed the presence of a new biphenyl, macrabiphenyl A, which was successfully elucidated by means of spectroscopic methods (HRESIMS and 1D and 2D NMR). The α-glucosidase inhibitory evaluation indicated that the new compound was weakly active against the enzyme.

The chemical profiles and cytotoxicity of gaharu bouya oil from Borneo's Gonystylus bancanus wood

Gaharu bouya oil obtained from distillation of the woods from Gonystylus genus has attracted essential oil industry interest. However, the information about gaharu bouya essential oil profile is limited. The presence of Gonystylus species is also critically endangered on the IUCN Red List. Therefore, exploring the -omics profiles of Gonystylus bancanus, a native plant from Borneo Island, is important for Indonesia to conserve the population. This research investigated the metabolite profiling of G. bancanus oil, especially the volatile components of its essential oils. Distillations were performed in two technical ways: hydrodistillation on a laboratory scale and steam distillation on an industrial scale. According to LC-MS and GC-MS profiles, both essential oils displayed similar chemical compositions. This article also discusses the similarity of the chemical contents of gaharu bouya oil and agarwood oil from the gaharu superior type (Aquilaria) to support the value of the oil. This research also investigated the cytotoxicity of gaharu bouya oil against three cell lines: HeLa, MCF-7, and HT-29.

Phytochemical profile and diverse pharmacology of Garcinia celebica L

Garcinia celebica L. syn. Garcinia hombroniana Pierre belongs to the family Clusiaceae, is indigenous to Southeast Asian countries. This review aims to provide updated, comprehensive and categorized information on the phytoconstituents and pharmacological effects of this species. The data collection mainly involved searches through databases named Scopus, Google Scholar, Pubmed and Springer Link. Approximately 100 phytochemicals were recorded in this review, with various classes of compounds such as triterpenoids, flavonoids, benzophenones, xanthones, depsidones and sterols identified. The most abundant compounds isolated belong to two chemical classes: triterpenoids and xanthones. Their extracts and pure compounds have been reported for their antibacterial, antiparasitic, hepatoprotective, antioxidant, antidiabetic, antituberculosis, antiplatelet aggregation, anti-neuraminidase and cholinesterase inhibitory activities. This review will provide a comprehensive understanding between the phytochemical components and its medicinal uses that may serve as a valuable resource for future drug development.

Antiplasmodial and anticancer activities of xanthones isolated from Garcinia bancana Miq

This report describes the isolation and characterization of xanthones from Garcinia bancana Miq. and evaluates their antiplasmodial and anticancer activities. Macluraxanthone (1), isojacareubin (2), and gerontoxanthone C (3) were isolated from the stem bark of G. bancana Miq. for the first time. In silico molecular docking studies revealed the hydrogen bonding and steric interactions between xanthones (1-3) and PfLDH/VEGFR2. The in vitro antiplasmodial activity was assayed against the chloroquine-sensitive Plasmodium falciparum strain 3D7 by the lactate dehydrogenase (LDH) method. The anticancer evaluation was evaluated against the A549, MCF-7, HeLa, and B-16 cancer cell lines. Compounds (1) (IC50 8.45-16.71 μM) and (3) (IC50 9.69-14.86 μM) showed more potent anticancer activity than compound (2) (IC50 25.46-31.31 μM), as well for their antiplasmodial activity (4.28 μM, 5.52 μM, 11.45 μM). Our findings indicated the potential of G. bancana Miq. as a natural resource of antiplasmodial and anticancer compounds.

Antioxidant and α-glucosidase inhibitory activities of compound isolated from Stachytarpheta jamaicensis (L) Vahl. leaves

Stachytarpheta jamaicensis is one of the folk medicines used for the treatment of diabetes in Ambon, Indonesia, but there are limited studies on the bioactivities of its constituents. This study aims to assess the antioxidant and antidiabetic activities of four extracts of S. jamaicensis leaves extracted using several solvents. Bioassay guided fractionation on each extract establishes for exploring S. jamaicensis leaves active compounds. The antioxidant was evaluated using the DPPH and ABTS methods, while the α-glucosidase inhibitory was carried out in vitro assay. The results showed that the methanol extract of S. jamaicensis leaves displays inhibition of DPPH, ABTS and α-glucosidase activity compared to other solvent extracts. Furthermore, 6β-hydroxyipolamiide was successfully isolated from the methanol extract of S. jamicensis leaves which was reported to have α-glucosidase inhibitory activity with an IC50 of 539.17 μg/mL. Based on the results, S. jamaicensis could be recommended as an antioxidant and antidiabetic agent.

Guttiferone BL from the Fruits of Allanblackia gabonensis Induces Mitochondrial-Dependent Apoptosis in PA-1 Ovarian Cancer Cells

Despite the recent advancement of treatment strategies, cancer ranks 2^nd among the causes of death globally. Phytochemicals have gained popularity as an alternate therapeutic strategy due to their nontoxic nature. Here, we have investigated the anticancer properties of guttiferone BL (GBL) along with four known compounds previously isolated from Allanblackia gabonensis. The cytotoxicity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The study was extended for the assessment of the effect of GBL in PA-1 cells apoptosis induction, cell cycle distribution, and change in mitochondrial membrane potential using flow cytometry, Western blot analysis, and real-time PCR. Among the five tested compounds, GBL displayed significant antiproliferative effects against all tested human cancer cells (IC₅₀ < 10μM). Moreover, GBL exhibited no significant cytotoxicity towards normal ovarian epithelial cell line (IOSE 364) up to 50 μM. GBL induced sub-G₀ cell cycle arrest and significant upregulation of cell cycle regulatory proteins of ovarian cancer cell PA-1. Furthermore, GBL induced its apoptosis as depicted by the accumulation of cells both at the early and late apoptotic phase in Annexin V/PI assay. In addition, it decreased the PA-1 mitochondrial membrane potential and promoted upregulation of caspase-3, caspase-9, and Bax and downregulation of Bcl-2. GBL also showed a dose-dependent inhibition of PA-1 migration. Altogether, this study reveals that guttiferone BL, studied herein for the first time, exhibits efficient antiproliferative activity by the induction of apoptosis through the mitochondrial-dependent pathway. Its investigation as a therapeutic agent against human cancers especially ovarian cancer should be envisaged.

Antidiabetic, cytotoxic and antioxidant activities of Rhodomyrtus tomentosa leaf extracts

As part of our project on exploring Indonesian medicinal plants for antidiabetic and anticancer agents, this study was conducted to investigate the total phenolic and flavonoid contents, and antioxidant, cytotoxic and antidiabetic properties of R. tomentosa leaf extracts. The antioxidant activity was tested using DPPH, ABTS, and FRAP methods. In vitro cytotoxic assay was performed against MCF-7, HeLa, A549, and B16 cancer cell lines. The in vitro antidiabetic testing was determined using α-glucosidase and α-amylase inhibitory evaluation, while STZ-induced diabetic rats were used for in vivo study. The highest values of total phenolic (191.97 ± 0.19 mg GAE g-1) and flavonoid (29.11 ± 0.05 mg QE g-1) contents were recorded in methanolic extract. This extract also showed the highest DPPH and ABTS activities with IC50 values of 7.79 ± 0.03 and 4.03 ± 0.02 μg mL-1, respectively, as well as the highest FRAP activity with a value of 64.05 ± 0.54 μM Fe2+ g-1. The methanol extract had cytotoxicity against MCF-7, HeLa, A549, and B16 cancer cell lines with IC50 values of 123.49 ± 0.79, 28.28 ± 0.17, 168.88 ± 1.14, and 42.44 ± 0.18 μg mL-1, respectively. In vitro antidiabetic evaluation indicated that the MeOH extract inhibited α-glucosidase and α-amylase with IC50 values of 45.73 ± 1.06 and 41.31 ± 1.12 μg mL-1, respectively. A dose of 400 mg kg-1 body weight of the MeOH extract reduced rats' blood glucose rate and serum blood glucose by 48.51% and 17.73%, respectively after 15 days of treatment. Taken together, these findings suggested that the methanolic extract of R. tomentosa leaves can be used as a potential source of antioxidant, cytotoxic, and antidiabetic agents.