Isopimarane-type diterpenoids from the rhizomes of Kaempferia galanga L. and their biological activities

Six new phenylpropanoids from Kaempferia galanga L. and their anti-inflammatory activity

Kaempferia galanga L. is an aromatic medicinal plant belonging to the Zingiberaceae family. Its rhizome has been widely used as traditional Chinese medicine and a flavor spice for a long time. In this study, six previously undescribed phenylpropanoids, including four [2+2]-cycloaddition-derived cyclobutane natural products (1-4), and two phenylpropanoids (5-6) were isolated from the rhizomes of K. galanga L. Their structures were elucidated by spectroscopic methods, single-crystal X-ray diffraction, NMR calculation, and ECD spectra calculation. These cyclobutane derivatives were isolated from K. galanga for the first time. Furthermore, compounds 1-6 were evaluated for the potential inhibitory activities on NO production and NF-κB nuclear translocation in LPS-triggered RAW 264.7 macrophages. The results showed that the isolated compounds have a moderate anti-inflammatory activity measured on their potency to inhibit NO production and the expression of iNOS and COX-2. Additionally, compound 2 effectively suppressed NF-κB nuclear translocation at a concentration of 40 μM.

Albiflorenes A-L, polyoxygenated cyclohex(a/e)ne diterpene esters from Kaempferia albiflora

Twelve polyoxygenated cyclohex(a/e)ne diterpene esters, named albiflorenes A-L (1-12), were isolated from the whole plants of Kaempferia albiflora, known as "Prao Mang Mum." Their structures and relative stereochemistry were determined by extensive spectroscopic analysis. Furthermore, the comparison of experimental electronic circular dichroism (ECD) curves with the curves predicted by TDDFT was used to determine the absolute configurations. Albiflorenes contain polyoxygenated cyclohexane (or cyclohexene) derivatives, which are linked to either isopimarane or abietane diterpene acid units. The discovery marks the first occurrence of a conjugate between polyoxygenated cyclohexane (or cyclohexene) rings and diterpenoids. Among the isolates, albiflorene C specifically exhibited antibacterial activity against Bacillus cereus with MIC and MBC values of 3.13 and 6.25 μg/mL, respectively.

Antimicrobial and Antiproliferative Effects of Zingiberaceae Oils: A Natural Solution for Oral Health

Essential oils have been recognised for their potential benefits in oral care. The aim of this study was to evaluate the antibacterial and antiproliferative activity of essential oils derived from four Zingiberaceae species. A combination of GC/MS and GC-FID was employed to analyse these essential oils. The results showed that β-myrcene (79.77 %) followed by ethyl-cinnamate (40.14 %), β-curcumene (34.90 %), and alloaromadendrene (25.15 %) as the primary constituents of Curcuma mangga, Curcuma xanthorrhiza, Kaempferia galanga and Curcuma aeruginosa, respectively. The Zingiberaceae oils were tested for their antibacterial activity against oral bacteria using the disc diffusion test. Curcuma xanthorrhiza oil showed the largest inhibition zones against Streptococcus mitis (19.50±2.22 mm) and Streptococcus sanguinis (15.04±3.05 mm). Similarly, Curcuma mangga oil exhibited significant antibacterial activity against Streptococcus mutans (12.55±0.45 mm) and mixed oral bacteria (15.03±3.82 mm). Furthermore, the MTT viability assay revealed moderate inhibitory activity of these essential oils against H103 and ORL-204 oral cancer cells. The study findings demonstrate that Curcuma xanthorrhiza and Curcuma mangga essential oils have potent antibacterial properties, suggesting their potential use as natural alternatives to synthetic antibacterial agents in oral care products. However, further investigations are necessary to fully explore their therapeutic applications.

Yuexiandajisu diterpenoids from Euphorbia ebracteolata Hayata (Langdu roots): An overview

The roots of the plant Euphorbia ebracteolata Hayata (Yue Xian Da Ji) are commonly used in traditional Chinese medicine to treat multiple diseases such as chronic liver diseases, oedema, pulmonary diseases and cancer. It is the main ingredient of the TCM called Langdu which can be prepared also from roots of E. fischeriana Steud. and occasionally from Stellera chamaejasme species. Numerous bioactive natural products have been isolated from E. ebracteolata including a large diversity of diterpenoids with anti-inflammatory and anticancer properties. One little series of compounds has been named yuexiandajisu (A, B, C, D, D₁, E, F) which comprises two casbane-, one isopimarane-, two abietane-, and two rosane-type diterpenes including a dimeric molecule. The origin, structural diversity and properties of these little-known natural products is discussed here. Several of these compounds have been identified in the roots of other Euphorbia species, notably the potent phytotoxic agent yuexiandajisu C. The abietane diterpenes yuexiandajisu D-E exhibit marked anticancer properties but their mechanism of action remains unresolved. The dimeric compound, renamed yuexiandajisu D₁, also exhibit anti-proliferative properties against cancer cell lines, unlike the rosane diterpene yuexiandajisu F. The structural or functional analogy with other diterpenoids is discussed.