New 2-arylbenzofurans from the root bark of Artocarpus lakoocha

Pharmacological effects of Artocarpus lakoocha methanol extract on inhibition of squalene synthase and other downstream enzymes of the cholesterol synthesis pathway

CONTEXT

Artocarpus lakoocha Roxb. (Moraceae) is reported to possess antioxidant, anti-inflammatory, and anti-skin ageing agents.

OBJECTIVE

This study evaluates the pharmacological effects of A. lakoocha leaves methanol extract on enzymes involved in the cholesterol synthesis pathway in high-fat diet-induced hyperlipidemic rats.

MATERIALS AND METHODS

Twenty-four male Wistar rats, weighing approximately 180-220 g, were divided into four groups: control, diseased (hyperlipidemic), A. lakoocha leaves extract treated, and simvastatin treated. The rats were fed with high-fat diet for 2 months to induce hyperlipidaemia, afterward, experimental groups received A. lakoocha leaves methanol extract (250 mg/kg) and simvastatin (10 mg/kg) orally until the 89th day of the experiment, while the diseased group continued to receive high-fat diet along with normal saline.

RESULTS

It was found that A. lakoocha extract significantly lowered the serum total cholesterol, triglycerides, and low-density lipoprotein (LDL) levels, while effectively increasing serum high-density lipoprotein (HDL) levels as compared to the diseased group (p ≤ 0.05). The mRNA expression levels of squalene synthase and HMG-CoA reductase were found to be effectively down-regulated after the treatment with A. lakoocha leaves extract (17.45 ± 2.48 vs. 31.91 ± 5.292 and 5.85 ± 3.164 vs. 37.37 ± 6.492) and simvastatin (7.148 ± 0.76 vs. 31.91 ± 5.292, and 3.098 ± 2.09 vs. 37.37 ± 6.492) as compared to the diseased group.

DISCUSSION AND CONCLUSIONS

The results suggested that A. lakoocha leaves extract have observable beneficial effects on inhibition of enzymes involved in cholesterol synthesis pathway and improve lipid profile analogous to simvastatin.

A Literature Review of Artocarpus lacucha Focusing on the Phytochemical Constituents and Pharmacological Properties of the Plant

Studies have shown that approximately two-thirds of the plant species in the world have some medicinal value. Artocarpus lakoocha is a synonym for Artocarpus lacucha and is a plant that can be found in Indonesia. This medicinal plant has been used to treat many diseases. (1) Objective: This article discusses the scientific investigations carried out on A. lacucha, namely the plant’s chemical content, pharmacological activity, and active compounds. (2) Methods: The design of this study was based on an article that was a review of previous research. A search for relevant publications over the past ten years (2012–2022) using data from Pubmed, Proquest, Ebsco, ScienceDirect, and Google Scholar resulted in the discovery of 369 articles. (3) Results: Fifty relevant articles investigate A. lacucha’s substances and their applications in the health field. The presence of secondary metabolites and bioactive compounds has been reported, which is evidence that A. lacucha possesses antidiarrheal, immunostimulant, anticholesterol, and hepatoprotective agents. (4) Conclusions: Mobe (A. lacucha) is a plant native to North Sumatra, Indonesia. This plant is efficacious as an antioxidant, antibacterial, antidiarrheal, anti-inflammatory, analgesic, antinociceptive, schistosomicidal, hepatoprotective, neuroprotective, cytotoxic, antiglycation, and anticholesterol, and can also be used for anti-aging and wound healing. In addition to its various benefits, it turns out that this plant also has many active compounds that are useful to the health sector, especially the pharmaceutical field.

Highly Aromatic Flavan-3-ol Derivatives from Palaeotropical Artocarpus lacucha Buch.-Ham Possess Radical Scavenging and Antiproliferative Properties

Phytochemical investigation of leaves and stembark of Artocarpus lacucha collected in Thailand resulted in three yet undescribed isomeric flavan-3-ol derivatives (1–3), the four known compounds gambircatechol (4), (+)-catechin (5), (+)-afzelechin (6) and the stilbene oxyresveratrol (7). Compounds 1 to 3 feature 6/6/5/6/5/6 core structures. All structures were deduced by NMR and MS, while density functional theory (DFT) calculations on B3LYP theory level were performed of compounds 1 to 3 to support the stereochemistry in positions 2 and 3 in the C-ring. Possible biosynthetic pathways leading to 4 are discussed. The DPPH assay revealed high radical scavenging activities for 1 (EC₅₀ = 9.4 ± 1.0 µmol mL⁻¹), 2 (12.2 ± 1.1), 3 (10.0 ± 1.5) and 4 (19.0 ± 2.6), remarkably lower than ascorbic acid (EC₅₀ = 34.9) and α-tocopherol (EC₅₀ = 48.6). A cytotoxicity assay revealed moderate but consistent antiproliferative properties of 1 in CH1/PA-1 (ovarian teratocarcinoma) and SW480 (colon carcinoma) cells, with IC₅₀ values of 25 ± 6 and 34 ± 4 µM, respectively, whereas effects in A549 (non-small cell lung cancer) cells were rather negligible. The performed DCFH-DA assay of 1 in the former cell lines confirmed potent antioxidative effects even in the cellular environment.

Chiral separation, absolute configuration, and bioactivity of two pairs of flavonoid enantiomers from Morus nigra

An undescribed isoprenylated flavonol racemate, nigranol C, with an unprecedented 7/6/6 ring system, was isolated from the twigs of Morus nigra L. The structure was assigned through a comprehensive analysis of HRMS, IR, and NMR data. Chiral separation of nigranol C was successfully carried out to yield a pair of enantiomers, nigranol C-a and nigranol C-b, whose absolute configurations were determined by ECD calculation. A plausible biogenetic pathway for nigranol C was proposed. A previously isolated sanggenon-type flavonone racemate, nigragenon E, was also well resolved by chiral HPLC to offer another pair of enantiomers, nigragenon E-a and nigragenon E-b, whose stereo configurations were determined by ECD data. All of the isolated compounds showed prominent α-glucosidase inhibitory activities with IC₅₀ values ranging from 9.79 to 30.21 μM, while only the sanggenon-type flavonones exhibited tyrosinase inhibitory effects comparable to that of the positive control, kojic acid, the IC₅₀ value of which was 27.14 μM. In addition, it was found that the stereo configurations of these compounds seemed to play a negligible role in their inhibitory activities towards the two enzymes.

New 2-arylbenzofurans from the root bark of Artocarpus gomezianus and their α-glucosidase inhibitory activity

Two new 2-arylbenzofurans, namely 13-O-methyllakoochin B (1) and artogomezianin (2), were isolated from the root bark of Artocarpus gomezianus, along with six known compounds (3-8). The structures of new compounds were determined by spectroscopic and chemical methods. All of the isolates were evaluated for their α-glucosidase inhibitory activity. Artogomezianin (2) and lakoochin A (3) exhibited strong α-glucosidase inhibitory activity with IC₅₀ values of 18.25 and 26.19 µM, respectively, as compared with the positive control acarbose.

2-Arylbenzofurans from Artocarpus lakoocha and methyl ether analogs with potent cholinesterase inhibitory activity

In vitro screening for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of the Artocarpus lakoocha root-bark extracts revealed interesting results. Bioassay-guided fractionation resulted in the isolation of two new (1 and 2) and six known 2-arylbenzofurans 3-8, along with one stilbenoid 9 and one flavonoid 10. The structures of the isolated compounds were elucidated by UV, IR, 1D- and 2D-NMR and MS spectroscopic data analysis. Compounds 4, 6 and 7 exhibited more potent AChE inhibitory activity (IC₅₀ = 0.87-1.10 μM) than the reference drug, galantamine. Compounds 4, 8 and 9 displayed greater BChE inhibition than the standard drug. The preferential inhibition of BChE over AChE indicated that 4 also showed a promising dual AChE and BChE inhibitor. The synthetic mono-methylated analogs 4a-c and 6a-b were found to be good BChE inhibitors with IC₅₀ values ranging between 0.31 and 1.11 μM. Based on the docking studies, compounds 4 and 6 are well-fitted in the catalytic triad of AChE. Compounds 4 and 6 showed different binding orientations on BChE, and the most potent BChE inhibitor 4 occupied dual binding to both CAS and PAS more efficiently.

Flavonoids with Anti-HSV Activity from the Root Bark of Artocarpus Lakoocha

From the MeOH extract of the root bark of Artocarpus lakoocha, a new compound 5,7,2’,4’-tetrahydroxy-6-geranyl-3-prenyl-flavone (1) was isolated, along with three known flavonoids (+)-afzelechin-3- O-α-L-rhamnopyranoside (2), (+)-catechin (3) and cudraflavone C (4). Evaluation of these isolates for inhibitory effects against Herpes simplex virus (HSV) types 1 and 2 was carried out using the inactivation method. Compounds 1 and 4 showed moderate and weak activity against both types of HSV, respectively, whereas 2 and 3 were devoid of activity.

Flavonoid and stilbenoid production in callus cultures of Artocarpus lakoocha

Callus cultures of Artocarpus lakoocha Roxb., established from seedling explants and maintained on woody plant medium containing 1mg/l 2,4-dichlorophenoxyacetic acid and 1mg/l benzyladenine, were studied for their chemical constituents and biosynthetic potential of secondary metabolites. Four prenylflavones and prenylated stilbenes, along with nine known polyphenolic compounds, were isolated and elucidated for their structures through extensive analysis of their NMR and MS data. Among the 13 isolates, it appeared that seven of them are prenylated derivatives of 5,7,2',4'-tetrahydroxyflavones, and four are prenylated derivatives of 2,4,3',5'-tetrahydroxystilbene (oxyresveratrol), suggesting that the biosynthetic pathways of these two polyphenolic groups and their prenylating enzymes are highly expressed in A. lakoocha callus cultures. A study on the growth-product relationship of the callus cultures showed that the secondary metabolites were all formed simultaneously during the rapid growth phase of the culture cycle, with various prenylflavones, and a prenylated stilbene as major constituents. In assays for DPPH free radical scavenging activity and tyrosinase inhibitory potential, the stilbenoids appeared to possess moderate effects, whereas the flavonoids showed only weak activity.