Total Synthesis of Lignan Lactone (-)-Hinokinin

Optimization of (-)-cubebin biotransformation to (-)-hinokinin by the marine fungus Absidia coerulea 3A9

The genus Absidia is widely used in the biotransformation of different classes of natural products. This study evaluates the ability of the Absidia coerulea 3A9 marine derived strain isolated from the ascidian Distaplia stilyfera to perform biotransformations by conducting assays with (-)-cubebin, as substrate. The experiment was optimized using the experimental design proposed by Plackett-Burman for seven factors and eight experiments, to establish the biotransformation conditions that would allow maximum production of biotransformed dibenzylbutyrolactone (-)-hinokinin. An analytical method based on Reverse-Phase-High Performance Liquid Chromatography (RP-HPLC) was developed to quantify the fungal biotransformation product. The factor that influenced the (-)-hinokinin peak area the most positively was the percentage of seawater (%seawater) given that its %relative standard deviation (%RSD) showed a 32.92% deviation from the real value.

Biotechnological Approach for the Production of Enantiomeric Hydroxylactones Derived from Benzaldehyde and Evaluation of Their Cytotoxic Activity

The β-aryl-δ-halo-γ-lactones are known for their antiproliferative activity towards numerous cancer cell lines. The aim of this study was to obtain in the biotransformation process new β-aryl-δ-hydroxy-γ-lactones and compare their activity with the antiproliferative activity of parent compounds. The racemic cis-5-(1-iodoethyl)-4-phenyldihydrofuran-2-one as well as separate enantiomers were transformed in fungal cultures. Among ten tested biocatalysts, three (Absidia cylindrospora AM336, Absidia glauca AM254, and Fusarium culmorum AM10) were able to catalyze the hydrolytic dehalogenation process. The biotransformations processes were highly stereoselective and enantiomerically pure hydroxylactones were obtained (ee ≥ 99%). The iodo- and hydroxylactone enantiomers were subjected to cytotoxic activity evaluation on canine leukemia and lymphoma cell lines. The iodolactones exhibited higher biological potential towards tested cell lines than hydroxylactones. Higher cytotoxic potential was also characteristic for (+)-(4S,5S,6R)-enantiomer of iodolactone compared to its antipode.

Cytotoxicity and selectiveness of Brazilian Piper species towards oral carcinoma cells

BACKGROUND

Oral squamous cell carcinoma (OSCC) is one of the ten most common types of cancer worldwide. Plants of the genusPiper are used in traditional medicine to treat cancer, and they have a vast diversity of phytochemicals with cytotoxic potential. Purpose and Study Design: In this work, we analyzed the cytotoxic and selective potential of extracts and semipurified fractions of Piper mollicomum (PM), Piper truncatum (PT), Piper cernuum (PC), Piper arboreum (PA), and Piper cabralanum (PCa) using three different OSCC cell lines (SCC4, SCC9 and SCC25), and we measured their in vivo toxicities and conducted chemical analyses of their active fractions.

RESULTS

The dichloromethane fractions of the crude methanolic extracts of the leaves of PM(-L-D), PC(-L-D) and PCa(-L-D) exhibited notable IC₅₀ values of 94.2, 47.2 and 47.5 μg/mL, respectively, and all three of these extracts were more active than carboplatin (172.3 μg/mL). The most selective fraction was PC-L-D, which exhibited SI > 4.5; less than 5% hemolysis; and no significant alterations in in vivo acute toxicology. The major constituents in active fractions were lignans (PC-L-D and PCa-L-D) and chromenes (PM-L-D).

CONCLUSION

PC-L-D demonstrated great potential for further development as an anticancer drug and could be the key to developing more effective and less toxic therapies against oral cancer.

Anti-cholinesterase Activity of Crude Drugs Selected from the Ingredients of Incense Sticks and Heartwood of Chamaecyparis obtusa

An effective agent for the treatment and/or prevention of Alzheimer's disease (AD) is needed due to the number of patients in the acute curve. In our research program to investigate effective agents for AD, we focused on crude drugs which consisted of incense sticks widely used in Asian countries including Japan. We selected 9 drugs as “aromatic” crude drugs and 2 as basal crude drugs. Among the samples tested, the essential oil obtained from the leaf of Cryptomeria japonica showed the most potent anti-acetylcholinesterase activity with 64.8% of inhibition at 100 μg/mL. In addition, no sample showed significant inhibition against β-secretase. From these results, the crude drugs selected in this study may be effective for AD therapy rather than prevention. The active principles of anti-acetylcholinesterase were investigated by activity-guided fractionation, and kaur-16-ene, nezukol and ferruginol were successfully identified, the IC50 values were 640, 300 and 95 μM, respectively. Kaur-16-ene and nezukol inhibited acetylcholinesterase in the mixed type mode, while ferruginol inhibited it in the competitive mode. In addition, nezukol and ferruginol showed anti-butyrylcholinesterase activity, the IC50 values were 155 and 22 μM, respectively. We also focused on the heartwood of Chamaecyparis obtusa, since this tree has been used as a building material for the heartwood of C. japonica. Ethyl acetate extract of C. obtusa showed anti-acetylcholinesterase activity of 37.7% inhibition at 100 μg/mL. The active principle was determined to be (-)-hinokinin by activity-guided fractionation and the IC50 value was 176 μM. These results suggest that the leaf of C. japonica and heartwood of C. obtusa may be suitable agents for AD therapy when administered through the nasal system as an aroma supplement.

Medicinal Attributes of Lignans Extracted from Piper Cubeba: Current Developments

Lignans are a large class of natural products that have been isolated from many plants. They reveal diverse biological activities, especially antiviral and antitumor properties. From Piper cubeba, lignans of several classes can be isolated from the roots, rhizomes, stems, leaves, seeds, and fruits. Among its various chemical constituents, (-)-cubebin and (-)-hinokinin are found in significant quantities. Although they have been known for some time, during the last few decades their biological properties have been studied by several research groups. The cubebins have been identified as a lactol monomer and dimers as a mixture of diastereoisomers. Recently, their structural characterization and the synthesis of the possible structures have led to the correction of some earlier structural proposals. This review describes the more recent developments in the study of the medicinal attributes of cubebin and hinokinin extracted from Piper cubeba and the synthesis and biological testing of some analogues.