Artoindonesianins G-I, three new isoprenylated flavones from Artocarpus lanceifolius

Anti-cancer bioprospecting on medicinal plants from Indonesia: A review

The Indonesian archipelago is home to the second largest biodiversity in the world and is inhabited by more than 300 ethnic groups with a total population of more than 270 million. The indigenous population still rely on traditional medicine practices, especially the use of plant-based remedies. Although modern science-based exploration on Indonesian medicinal plants started with the European settlement in the archipelago in the 16th century, it was not until the 1970's that the phytochemistry of Indonesian medicinal plants was recognized for its potency. The need for new cancer cures to increase the quality of human life has led to the bioprospecting of medicinal plants including those of Indonesian origin. Despite published reports on the anticancer potency of Indonesian medicinal plants, to date there has been no comprehensive review on this topic. In this manuscript, we review the phytochemical and pharmacological studies on medicinal plants from Indonesia related to cancer therapy. Established databases (GARUDA, SciFinder, and PubMed) were used to collate data from 1990 to 2022, resulting in the description of 134 medicinal plants and their phytochemical and pharmacological properties including examples containing potent agents against breast, leukaemia, cervix, lung, and colon cancer cell lines based on in vitro bioassays and in vivo evaluation. These findings provide valuable insights into the bioprospecting of Indonesian medicinal plant providing directions for future studies, including the development of new therapeutics, both as botanicals or by using conventional dosage.

Total syntheses and antibacterial evaluations of cudraflavones A-C and related Flavones

The total syntheses of the natural prenylated flavones cudraflavones A-C (1-3), artoheterophyllin D (28) and artelasticin (29) are reported, along with the evaluations of their antibacterial activities. The key steps of the synthesis involved a Baker-Venkataraman rearrangement and an intramolecular cyclization for the construction of the flavone core and the regioselective formation of the pyran and isopentenyl scaffolds. The tested natural flavones 1-3 and 27-29 exhibited potent activity against S. aureus ATCC 29213, S. epidermidis ATCC 14990, E. faecalis ATCC 29212 and B. subtilis ATCC 6633 with MIC values ranging from 0.125 μg/mL to 16 μg/mL. Compound 3 displayed the strongest potency, with MIC values in the range between 0.125 and 1 μg/mL, as a potential candidate to combat G+ bacterial infections. Preliminary mechanism of action studies suggested that this compound killed bacteria by disrupting bacterial membrane integrity.

Two isoprenylated flavonoids from Dorstenia psilurus activate AMPK, stimulate glucose uptake, inhibit glucose production and lower glycemia

Root extracts of a Cameroon medicinal plant, Dorstenia psilurus, were purified by screening for AMP-activated protein kinase (AMPK) activation in incubated mouse embryo fibroblasts (MEFs). Two isoprenylated flavones that activated AMPK were isolated. Compound 1 was identified as artelasticin by high-resolution electrospray ionization mass spectrometry and 2D-NMR while its structural isomer, compound 2, was isolated for the first time and differed only by the position of one double bond on one isoprenyl substituent. Treatment of MEFs with purified compound 1 or compound 2 led to rapid and robust AMPK activation at low micromolar concentrations and increased the intracellular AMP:ATP ratio. In oxygen consumption experiments on isolated rat liver mitochondria, compound 1 and compound 2 inhibited complex II of the electron transport chain and in freeze-thawed mitochondria succinate dehydrogenase was inhibited. In incubated rat skeletal muscles, both compounds activated AMPK and stimulated glucose uptake. Moreover, these effects were lost in muscles pre-incubated with AMPK inhibitor SBI-0206965, suggesting AMPK dependency. Incubation of mouse hepatocytes with compound 1 or compound 2 led to AMPK activation, but glucose production was decreased in hepatocytes from both wild-type and AMPKβ1-/- mice, suggesting that this effect was not AMPK-dependent. However, when administered intraperitoneally to high-fat diet-induced insulin-resistant mice, compound 1 and compound 2 had blood glucose-lowering effects. In addition, compound 1 and compound 2 reduced the viability of several human cancer cells in culture. The flavonoids we have identified could be a starting point for the development of new drugs to treat type 2 diabetes.

Characterization and Identification of Prenylated Flavonoids from Artocarpus heterophyllus Lam. Roots by Quadrupole Time-Of-Flight and Linear Trap Quadrupole Orbitrap Mass Spectrometry

In this study, a combination of quadrupole time-of-flight mass spectrometry (Q-TOF-MS) and linear trap quadrupole orbitrap mass spectrometry (LTQ-Orbitrap-MS) was performed to investigate the fragmentation behaviors of prenylated flavonoids (PFs) from Artocarpus plants. Fifteen PFs were selected as the model molecules and divided into five types (groups A–E) according to their structural characteristics in terms of the position and existing form of prenyl substitution in the flavone skeleton. The LTQ-Orbitrap-MSⁿ spectra of the [M − H]⁻ ions for these compounds provided a wealth of structural information on the five different types of compounds. The main fragmentation pathways of group A were the ortho effect and retro Diels–Alder (RDA), and common losses of C₄H₁₀, CO, and CO₂. The compounds in group B easily lose C₆H₁₂, forming a stable structure of a 1,4-dienyl group, unlike those in group A. The fragmentation pathway for group C is characterized by obvious ^1,4A⁻, ^1,4B⁻ cracking of the C ring. The diagnostic fragmentation for group D is obvious RDA cracking of the C ring and the successive loss of CH₃ and H₂O in the LTQ-Orbitrap-MSⁿ spectra. Fragmentation with successive loss of CO or CO₂, ·CH₃, and CH₄ in the LTQ-Orbitrap-MSⁿ spectra formed the characteristics of group E. The summarized fragmentation rules were successfully exploited to identify PFs from Artocarpusheterophyllus, a well-known Artocarpus plant, which led to the identification of a total of 47 PFs in this plant.

Inventory, Constituents and Conservation of Biologically Important Sumatran Plants

An inventory of Sumatran medicinal plants, and reports on their chemistry and conservation carried out in the last three decades are reviewed.

Isoprenylated flavonoids and adipogenesis-promoting constituents from Morus nigra

Ten new isoprenylated flavonoids, nigrasins A-J (1-10), and three known compounds were isolated from the twigs of Morus nigra. Compounds 8 and 9 promoted adipogenesis, characterized by increased lipid droplet and triglyceride content in 3T3L1 cells, and induced up-regulation of the expression of adipocyte-specific genes, aP2 and GLUT4.

Prenylated flavonoids and related compounds of the Indonesian Artocarpus (Moraceae)

Several species of the genus Artocarpus (Moraceae) have been investigated in our laboratories during the last decade. Over 60 phenolic constituents have been discovered and characterized, including 27 new compounds from 13 Indonesian taxa of Artocarpus, namely A. champeden, A. lanceifolius, A. teysmanii, A. scortechinii, A. rotunda, A. maingayi, A. kemando, A. bracteata, A. altilis, A. fretessi, A. gomezianus, A. reticulatus and A. glaucus. The principal and the most pronounced features of these phenolic constituents are the assembly of an isoprenyl substituent at C-3 of a flavone skeleton by closure of an ether bridge or a carbon-carbon linkage with the B ring of the skeleton, which may further rearrange into xanthone to produce various classes of natural products. The structures of the new and unusual natural products are presented. Many of the metabolites also exhibit cytotoxic effect against murine leukemia P388 cells.

Furanoflavonoids: an overview

The review covers the phytochemistry and pharmacology of furanoflavonoids describing 291 compounds and containing 228 references.

Artoindonesianins X and Y, two isoprenylated 2-arylbenzofurans, from Artocarpus fretessi (Moraceae)

Two isoprenylated 2-arylbenzofurans, artoindonesianins X and Y (1-2), together with seven known flavonoids, have been isolated from the roots and tree bark of Artocarpus fretessi. Their structures were established on the basis of spectral analysis. Compounds 1 and 2 showed moderate activity against the brine shrimp Artemia salina.

Two oligostilbenes, cis- and trans-diptoindonesin B, from Dryobalanops oblongifolia

Two oligostilbenes, cis- and trans-diptoindonesin B, have been isolated from the tree bark of Dryobalanops oblongifolia (Dipterocarpaceae). The structures and relative configurations of both compounds were determined on the basis of spectroscopic evidence, including 2D-NMR spectroscopic analysis.

Flavonoids from Artocarpus lanceifolius

One new compound, 14-hydroxyartonin E (1), together with the known compound, artonin E (2), was isolated from Artocarpus lanceifolus. Their structures were elucidated by spectroscopic methods.

Artoindonesianins N and O, new prenylated stilbene and prenylated arylbenzofuran derivatives from Artocarpus gomezianus

A new prenylated stilbene, named artoindonesianin N (1) and a new prenylated arylbenzofuran, named artoindonesianin O (2), were isolated from Artocarpus gomezianus Wall. ex Trec. (Moraceae). Their structures were elucidated as 1 and 2 on the basis of spectroscopic evidence. Along with these new compounds, a known phenolic compound was also isolated from this plant and identified as oxyresveratrol (3).

Artoindonesianin P, a new prenylated flavone with cytotoxic activity from Artocarpus lanceifolius

A new prenylated flavone, named artoindonesianin P (1), was isolated from the tree bark of Artocarpus lanceifolius, together with three known related compounds, artobiloxanthone (2), cycloartobiloxanthone (3) and artonol B (4). The structure of artoindonesianin P 1 was determined on the basis of spectral evidence (MS, 1H and 13C NMR) and by comparison with known related compounds. Compounds 1-4 exhibited significant cytotoxicity against murine P388 leukemia cells.