Coumarins and flavones from the fruit and root extracts of Micromelum integerrimum

Syntheses of Minutuminolate and Related Coumarin Natural Products and Evaluation of Their TNF-α Inhibitory Activities

The concise syntheses of the coumarin natural product, minutuminolate (1), and its related natural products, 7-methoxy-8-(2-acetoxy-3-methyl-1-oxobut-2-enyl) coumarin (2) and muralatin I (3), were accomplished for the first time in 4-5 steps from the commercially available umbelliferone. The key step involves a palladium-catalyzed oxidative rearrangement reaction to assemble the α-acyloxyenone moiety in 1 and 2. The incorporation of this functionality enables the successful synthesis of coumarin 3 through an acidic hydrolysis reaction. The anti-inflammatory activities of the compounds were also evaluated against tumor necrosis factor-alpha production in lipopolysaccharides-stimulated RAW264.7 cells. Our developed synthetic route will facilitate the development of analogues and derivatives of 1-3 with potent anti-inflammatory activities.

Coumarins and Gastrointestinal Cancer: A New Therapeutic Option?

Cancers of the gastrointestinal (GI) tract are often life-threatening malignancies, which can be a severe burden to the health care system. Globally, the mortality rate from gastrointestinal tumors has been increasing due to the lack of adequate diagnostic, prognostic, and therapeutic measures to combat these tumors. Coumarin is a natural product with remarkable antitumor activity, and it is widely found in various natural plant sources. Researchers have explored coumarin and its related derivatives to investigate their antitumor activity, and the potential molecular mechanisms involved. These mechanisms include hormone antagonists, alkylating agents, inhibitors of angiogenesis, inhibitors of topoisomerase, inducers of apoptosis, agents with antimitotic activity, telomerase inhibitors, inhibitors of human carbonic anhydrase, as well as other potential mechanisms. Consequently, drug design and discovery scientists and medicinal chemists have collaborated to identify new coumarin-related agents in order to produce more effective antitumor drugs against GI cancers. Herein, we summarize the therapeutic effects of coumarin and its derivatives against GI cancer.

Indole alkaloids from the leaves of Ravenia spectabilis engl. with activity against pancreatic cancer cell line

Two previously undescribed indole alkaloids, 3-prenyl-5(3-keto-but-1-enyl) indole and 3-prenyl-indole-5-carbaldehyde, the structurally-related 3,5-diprenyl indole and four known alkaloids were isolated from the leaves of Ravenia spectabilis Engl. Structures were elucidated based on nuclear magnetic resonance (1D and 2D NMR) spectroscopic and mass spectrometric analysis. The previously undescribed compounds isolated were subsequently screened against the HeLa (human cervical cancer), MIA PaCa-2 (human pancreatic adenocarcinoma) and A549 (lung cancer) cell lines. Among the isolated compounds, 3,5-diprenyl indole was the most cytotoxic across all three cell lines (MIA PaCa-2 IC₅₀ = 9.5 ± 2.2 μM). Molecular modelling studies suggested DNA intercalation as the mode of action of these compounds.