Chemical composition and biological activities of essential oil of the Malaysian endemic Syzygium variolosum (King) Chantar. & J.Parn.

This study was designed to investigate the chemical composition of the essential oil of Syzygium variolosum (King) Chantar. & J.Parn. and their cytotoxicity, acetylcholinesterase, antityrosinase, and anti-inflammatory activities. In total, 32 chemical components were identified in the essential oil, which made up 98.9%. The essential oil is mainly composed of ß-elemene (20.2%), bicyclogermacrene (13.5%), viridiflorol (11.1%), globulol (8.6%), and selin-11-en-4α-ol (5.3%). Acetylcholinesterase, antityrosinase, and anti-inflammatory activities were evaluated with the Ellman method, mushroom tyrosinase, and lipoxygenase enzymes, respectively, while cytotoxicity was assessed using an MTT assay. The results showed that essential oil gave significant percentage inhibition (I%: acetylcholinesterase 35.2%, antityrosinase 42.5%, lipoxygenase 48.6%). Furthermore, the essential oil exhibited cytotoxicity against three cancer cell lines, HepG2, MCF7, and A549, with IC50 values ranging from 90.2 to 95.2 µg/mL. The current study highlights the potential of the use of essential oils as an alternative to the development of pharmaceutical antichemopreventives or cosmetics.

Intermedianin, a new furofuran lignan from the leaves of Knema intermedia Warb.

Phytochemical investigation of the leaves of Knema intermedia has led to the isolation of a new furofuran lignan, intermedianin 1 together with five known lignans, α-cubebin 2, ß-cubebin 3, bicubebin A 4, bicubebin B 5, and bicubebin C 6. The characterisation and structural elucidation of the isolated compounds were established by extensive spectroscopic data analysis and comparison with literature data. The antifungal activity was tested using the broth microdilution assay, whereas the microbial biofilms were determined using a semi-quantitative static biofilm. Compound 1 exhibited activity against C. albicans, C. lusitanae, and C. auris, (each with MIC/MFC value 250 µg/mL) and increased the biofilm of C. auris (64.07 ± 3.83%) and Candida lusitanae (62.90 ± 3.41%) when treated with 500 µg/mL.

Essential oils composition of Litsea glauca and Litsea fulva and their anticholinesterase inhibitory activity.

This study was designed to examine the essential oils compositions of Litsea glauca Siebold and Litsea fulva Fern.-Vill. growing in Malaysia. The essential oils were achieved by hydrodistillation and fully characterized by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The study identified 17 and 19 components from the leaf oils from L. glauca (80.7%) and L. fulva (81.5%), respectively. The major components of L. glauca oil were ß-selinene (30.8%), ß-calacorene (11.3%), tridecanal (7.6%), isophytol (4.8%) and ß-eudesmol (4.5%); whereas in L. fulva oil gave ß-caryophyllene (27.8%), caryophyllene oxide (12.8%), α-cadinol (6.3%), (E)-nerolidol (5.7%), ß-selinene (5.5%) and tridecanal (5.0%). Anticholinesterase activity was evaluated using Ellman method. The essential oils showed moderate inhibitory activity on acetylcholinesterase and butyrylcholinesterase assays. Our findings demonstrate that the essential oil could be very useful for the characterization, pharmaceutical, and therapeutic applications of the essential oil from the genus Litsea.

Lepiginosides A-D: three new triterpenoid saponins and a new farnesyl glycoside from the stembarks of Lepisanthes rubiginosa (roxb.) leenh.

Phytochemical investigation of methanolic extract of L. rubiginosa using modern chromatographic techniques has led to the isolation of three new triterpenoid saponins, lepiginosides A-C (1-3), a new farnesyl glycoside, lepiginoside D (4), together with lepisantheside B (5) and gleditsoside C (6). The characterization and structural elucidation of the isolated compounds were established by extensive spectroscopic data analysis and comparison with literature data. Moreover, the antibacterial activity against seven bacteria, but none is active.

Chemical composition of essential oil from Lindera caesia Reinw. ex Fern.-Vill. and its antifungal, antibiofilm, and molecular docking studies.

The chemical composition, antifungal, antibiofilm, and molecular docking studies of the essential oil obtained from Lindera caesia were investigated. A total of thirty-nine components (96.7%) were identified using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The major components included terpinen-4-ol (26.3%), neo-intermedeol (23.2%), eudesma-4,11-dien-3-one (10.4%), and o-cymene (5.3%). The antifungal activity was tested against Candida albicans and Streptococcus mutans using the broth microdilution assay, whereas the microbial biofilms were determined using a semi-quantitative static biofilm. The essential oil exhibited activity against C. albicans (MIC 125 µg/mL) and S. mutans (MIC 250 µg/mL), and increased the biofilm of C. albicans by 31.25% when treated with 500 µg/mL. The molecular docking study shows neo-intermedeol, eudesma-4,11-dien-3-one, α-selinene, and ß-selinene as the good candidate to target Erg11 with a binding energy of -7.3 kcal/mol. These findings demonstrated that the essential oil may have potential in dental application for caries prevention.

Phytoconstituents of Endiandra kingiana; antidiabetic effects and molecular docking studies on alpha-amylase and alpha-glucosidase.

Phytochemical investigation on the bark of E. kingiana plant afforded ten compounds, including six polyketides namely kingianin A 1, kingianin B 2, kingianin E 3, kingianin F 4, kingianin K 5 and kingianin L 6, three endiandric acids; kingianic acid A 7, tsangibeilin B 8 and endiandric acid M 9, and one sesquiterpene; daibuoxide 10. All compounds were separated as racemic mixture by recycling high-performance liquid chromatography (RHPLC), except for daibuoxide. Their structures were elucidated by detailed spectroscopic and comparative literature data analysis. This is the first report on the presence of the sesquiterpene; daibuoxide in Endiandra genus. In vitro enzymatic bio-evaluation of the isolated compounds against α-amylase and α-glucosidase showed that 4 demonstrated the best α-amylase and α-glucosidase inhibitory activity with IC50 values of 181.54 ± 6.27 µg/mL and 237.87 ± 0.07 µg/mL, respectively. In addition, molecular docking analysis confirmed the α-amylase and α-glucosidase inhibitory activities demonstrated by 4.

Chemical composition of essential oil from Lindera subumbelliflora Kosterm and its effect on the susceptibility and biofilm activities of Candida albicans and Streptococcus mutans.

The chemical composition of the essential oil of Lindera subumbelliflora (Lauraceae) was investigated for the first time. The essential oil was obtained by hydrodistillation and fully characterised by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity of L. subumbelliflora essential oil was tested against Candida albicans and Streptococcus mutans using the broth microdilution assay, whereas the microbial biofilms were determined using a semi-quantitative static biofilm. A total of 28 components (99.6%) were successfully identified, which were characterised by ß-eudesmol (14.6%), cis-α-bergamotene (11.0%), α-copaene (8.5%), dodecen-1-ol (8.5%), and (E)-nerolidol (8.3%). The essential oil exhibited activity against Candida albicans and Streptococcus mutans with MIC values of 250 and 500 µg/mL, respectively. The essential oil increased the biofilm of Candida albicans by 38.25%, however, decreased the biofilm of Streptococcus mutans by 47.89% when treated with 500 µg/mL. Thus, the essential oil has a promising application in dentistry via inhibition of the growth of Candida albicans and Streptococcus mutans. However, the antibiofilm activity of the essential oil is only applicable for cariogenic Streptococcus mutans.

Secondary metabolites from endemic species Iris adriatica Trinajstic ex Mitic (Iridaceae).

This manuscript describes the first detailed chemical investigation of endemic species Iris adriatica, including isolation and structure elucidation. Chemical analyses of the rhizome CH2Cl2/MeOH (2:1) extract revealed fourteen secondary metabolites, mainly isoflavonoids. Among isoflavonoids, two groups have been found: nigricin-type and tectorigenin-type. Dominant group of the isolated compounds has been nigricin-type isoflavones: nigricin, nigricin-4'-(1-O-ß-D-glucopyranoside) and nigricin-4'-(1-O-ß-D-glucopyranosyl (1-6)-ß-D-glucopyranoside) with 2.5, 10 and 1% of the total extract, respectively. Irisxanthone - xanthone C-glucoside, ß-sitosterol, benzophenone and one of its derivatives have also been found. Nigricin-type isoflavonoids and irisxanthone can be considered as possible chemotaxonomic markers for I. adriatica. 5,3',5'-Trimethoxy-6,7-methylenedioxyisoflavone-4'-(1-O-ß-D-glucopyranoside) and benzophenone have been isolated from Iris species for the first time.

Comparative Study of the Volatile Components of Fresh and Fermented Flowers of Alnus sieboldiana (Betulaceae).

Analysis of the volatile components present in the fresh male and female flowers and young leaves shows that 2-phenylethanol is the major component in all these three organs, which play a significant role in the strong resinous aromatic odor. The male flowers contained styrene as a second major compound. The level of styrene does not affect the male flowers odor concentration. The level of ß-phenylethyl cinnamate and trans-methyl cinnamate in the fermented male flowers decreased as the fermentation time increased. This was due to the Penicillium enzymatic action on the fermented male flowers.

Volatile Components of the Stressed Liverwort Conocephalum conicum.

The Type-II Japanese Conocephalum conicum, which is known to have (+)-bornyl acetate as a marker compound, was put in the stressed condition to start biosynthesis of a phenyl propanoid, trans-methyl cinnamate. Analysis of the HS-SPME GC/MS of stressed C. conicum showed trans-methyl cinnamate as a major component. This phenomenon results in some confusion from the chemotype perspective since trans-methyl cinnamate is only present in type-III Japanese C. conicum.