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Natural products are important sources for drug discovery, especially anti-tumor drugs. β-Elemene, the prominent active ingredient extract from the rhizome of Curcuma wenyujin, is a representative natural product with broad anti-tumor activities. The main molecular mechanism of β-elemene is to inhibit tumor growth and proliferation, induce apoptosis, inhibit tumor cell invasion and metastasis, enhance the sensitivity of chemoradiotherapy, regulate the immune system, and reverse multidrug resistance (MDR). Elemene oral emulsion and elemene injection were approved by the China Food and Drug Administration (CFDA) for the treatment of various cancers and bone metastasis in 1994. However, the lipophilicity and low bioavailability limit its application. To discover better β-elemene-derived anti-tumor drugs with satisfying drug-like properties, researchers have modified its structure under the premise of not damaging the basic scaffold structure. In this review, we comprehensively discuss and summarize the potential anti-tumor mechanisms and the progress of structural modifications of β-elemene.

Though essential oils exhibit antibacterial activity against food pathogens, their underlying mechanism is understudied. We extracted ginger essential oil (GEO) using supercritical CO2 and steam distillation. A chemical composition comparison by GC-MS showed that the main components of the extracted GEOs were zingiberene and α-curcumene. Their antibacterial activity and associated mechanism against Staphylococcus aureus and Escherichia coli were investigated. The diameter of inhibition zone (DIZ) of GEO against S. aureus was 17.1 mm, with a minimum inhibition concentration (MIC) of 1.0 mg/mL, and minimum bactericide concentration (MBC) of 2.0 mg/mL. For E. coli, the DIZ was 12.3 mm with MIC and MBC values of 2.0 mg/mL and 4.0 mg/mL, respectively. The SDS-PAGE analysis revealed that some of the electrophoretic bacterial cell proteins bands disappeared with the increase in GEO concentration. Consequently, the nucleic acids content of bacterial suspension was raised significantly and the metabolic activity of bacteria was markedly decreased. GEO could thus inhibit the expression of some genes linked to bacterial energy metabolism, tricarboxylic acid cycle, cell membrane-related proteins, and DNA metabolism. Our findings speculate the bactericidal effects of GEO primarily through disruption of the bacterial cell membrane indicating its suitability in food perseveration.

Plant extracts contain many active compounds, which are tremendously fruitful for plant defence against several insect pests. The prime objectives of the present study were to calculate the extraction yield and to evaluate the leaf extracts of Citrullus colocynthis (L.), Cannabis indica (L.) and Artemisia argyi (L.) against Brevicoryne brassicae and to conduct biochemical analysis by gas chromatography-mass spectrometry (GC-MS). The results suggested that when using ethanol, C. colocynthis produced a high dry yield (12.45%), followed by that of C. indica and A. argyi , which were 12.37% and 10.95%, respectively. The toxicity results showed that A. argyi was toxic to B. brassicae with an LC 50 of 3.91 mg mL −1 , followed by the toxicity of C. colocynthis and C. indica , exhibiting LC 50 values of 6.26 and 10.04 mg mL −1 , respectively, which were obtained via a residual assay; with a contact assay, the LC 50 values of C. colocynthis , C. indica and A. argyi were 0.22 mg mL −1 , 1.96 and 2.87 mg mL −1 , respectively. The interaction of plant extracts, concentration and time revealed that the maximum mortality based on a concentration of 20 mg L −1 was 55.50%, the time-based mortality was 55% at 72 h of exposure, and the treatment-based mortality was 44.13% for A. argyi via the residual assay. On the other hand, the maximum concentration-based mortality was 74.44% at 20 mg mL −1 , the time-based mortality was 66.38% after 72 h of exposure, and 57.30% treatment-based mortality was afforded by A. argyi via the contact assay. The biochemical analysis presented ten constituents in both the A. argyi and C. colocynthis extracts and twenty in that of C. indica , corresponding to 99.80%, 99.99% and 97% of the total extracts, respectively. Moreover, the detected caryophylleneonides (sesquiterpenes), α-bisabolol and dronabinol (Δ 9 -THC) from C. indica and erucylamide and octasiloxane hexamethyl from C. colocynthis exhibited insecticidal properties, which might be responsible for aphid mortality. However, A. argyi was evaluated for the first time against B. brassicae . It was concluded that all the plant extracts possessed significant insecticidal properties and could be introduced as botanical insecticides after field evaluations.

The repellent capacity against Sitophilus zeamais and the in vitro inhibition on AChE of 11 essential oils, isolated from six plants of the northern region of Colombia, were assessed using a modified tunnel-type device and the Ellman colorimetric method, respectively. The results were as follows: (i) the degree of repellency (DR) of the EOs against S. zeamais was 20–68% (2 h) and 28–74% (4 h); (ii) the IC50 values on AChE were 5–36 µg/mL; likewise, the %inh. on AChE (1 µg/cm3 per EO) did not show any effect in 91% of the EO tested; (iii) six EOs (Bursera graveolens—bark, B. graveolens—leaves, B. simaruba—bark, Peperomia pellucida—leaves, Piper holtonii (1b*)—leaves, and P. reticulatum—leaves) exhibited a DR (53–74%) ≥ C+ (chlorpyrifos—61%), while all EOs were less active (8–60-fold) on AChE compared to chlorpyrifos (IC50 of 0.59 µg/mL). Based on the ANOVA/linear regression and multivariate analysis of data, some differences/similarities could be established, as well as identifying the most active EOs (five: B. simaruba—bark, Pep. Pellucida—leaves, P. holtonii (1b*)—leaves, B. graveolens—bark, and B. graveolens—leaves). Finally, these EOs were constituted by spathulenol (24%)/β-selinene (18%)/caryophyllene oxide (10%)—B. simaruba; carotol (44%)/dillapiole (21%)—Pep. pellucida; dillapiole (81% confirmed by 1H-/13C-NMR)—P. holtonii; mint furanone derivative (14%)/mint furanone (14%)—B. graveolens—bark; limonene (17%)/carvone (10%)—B. graveolens—leaves.

Hemp (Cannabis sativa L.) is currently one of the most controversial and promising crops. This study compared nine wild hemp (C. sativa spp. spontanea V.) accessions with 13 registered cultivars, eight breeding lines, and one cannabidiol (CBD) hemp strain belonging to C. sativa L. The first three groups had similar main essential oil (EO) constituents, but in different concentrations; the CBD hemp had a different EO profile. The concentration of the four major constituents in the industrial hemp lines and wild hemp accessions varied as follows: β-caryophyllene 11–22% and 15.4–29.6%; α-humulene 4.4–7.6% and 5.3–11.9%; caryophyllene oxide 8.6–13.7% and 0.2–31.2%; and humulene epoxide 2, 2.3–5.6% and 1.2–9.5%, respectively. The concentration of CBD in the EO of wild hemp varied from 6.9 to 52.4% of the total oil while CBD in the EO of the registered cultivars varied from 7.1 to 25%; CBD in the EO of the breeding lines and in the CBD strain varied from 6.4 to 25% and 7.4 to 8.8%, respectively. The concentrations of δ9-tetrahydrocannabinol (THC) in the EO of the three groups of hemp were significantly different, with the highest concentration being 3.5%. The EO of wild hemp had greater antimicrobial activity compared with the EO of registered cultivars. This is the first report to show that significant amounts of CBD could be accumulated in the EO of wild and registered cultivars of hemp following hydro-distillation. The amount of CBD in the EO can be greater than that in the EO of the USA strain used for commercial production of CBD. Furthermore, this is among the first reports that show greater antimicrobial activity of the EO of wild hemp vs. the EO of registered cultivars. The results suggest that wild hemp may offer an excellent opportunity for future breeding and the selection of cultivars with a desirable composition of the EO and possibly CBD-rich EO production.

Chlamydia are obligate intracellular bacterial pathogens affecting humans and animals, causing miscarriage, stillbirth, or weak fetuses in the late stages of pregnancy of goats and sheep. Because there is no commercial vaccine for chlamydia in animals, drug treatment has become the most effective curative method. Natural products, also known as secondary metabolites, are becoming one of the main sources used in new drug development because of their structural diversity and biodiversity. In natural products, plant sources play a major role in the development process of new drugs. In this study, five undescribed highly oxygenated bisabolane sesquiterpenes (Pararubin W, Pararubin X, Pararubin Y., Pararubin Z, and Pararubin AA) were isolated from whole plants of Ligularia narynensis. Their chemical structures were determined via analyses of HRESIMS, IR, 1D, and 2D NMR data, along with the assignment of their relative configurations. These compounds were tested for their anti-chlamydial activity. The results show that compounds 1 and 5 inhibited the growth of Chlamydia abortus in host cells in a dose-dependent manner.

The present study is designed to find out if sesquiterpenes, α-humulene (HUM), valencene (VAL), β-caryphyllene-oxide (CAO) and -nerolidol (NER), are able to improve the antiproliferative effect of classical cytostatic drugs, 5-fluorouracil (FU) and oxaliplatin (1,2-diaminocyclohexaneoxalato-platinum, OxPt), in colon cancer cell lines Caco-2 and SW-620. In addition, the possible mechanisms of sesquiterpene action are studied. The results show significant ability of HUM and especially of CAO to enhance the anti-proliferative effects of FU and OxPt in cancer cell lines Caco-2 and SW-620. On the other hand, VAL and NER are ineffective. The action of CAO could be partly based on its ability to disrupt the mitochondrial membrane potential and to activate initiator caspases, but other mechanisms are probably also involved. Based on these results, CAO seems to have the potential for combination therapy of colon cancers and deserves further study.

The cycloaddition of nitrile oxides and nitrilimines to one or both of the C=C double bonds of caryophyllene is described. The possibility of introducing five-membered fused and spiro-linked heterocycles into the structure of sesquiterpenes by the 1,3-dipolar cycloaddition reactions of nitrile oxides and nitrilimines to caryophyllene was demonstrated. As a result of these reactions, pharmacophore fragments of isoxazoline and pyrazoline are introduced into the structure of caryophyllene, which leads to an increase in the conformational rigidity of the molecule. A complete stereochemical assignment of 1,3-dipolar cycloaddition adducts to caryophyllene was carried out. The study of antiviral and cytotoxic activity for some heterocyclic derivatives synthesized in this work revealed relatively high biological activity of previously little-studied cycloaddition adducts at the exocyclic C=CH2 bond of caryophyllene. The effect of substituents in the synthesized heterocycles on biological activity was demonstrated. Compounds with a good inhibitory effect on the H1N1 influenza virus were revealed. The activity of the compound was demonstrated up to 6 h post infection, and this could be due to slight inhibiting activity against viral neuraminidase, necessary at the stage of progeny virion budding.

In the present study, the hexane extract from branches of Drimys brasiliensis (Winteraceae) displayed potent activity against Schistosoma mansoni parasites (100% mortality of the worms at 200 μg/mL). Bioactivity-guided fractionation afforded, in addition to the previously reported bioactive sesquiterpene 3,6-epidioxy-bisabola-1,10-diene, two chemically related drimane sesquiterpenes—polygodial (1) and 9-deoxymuzigadial (2). The anti-S. mansoni effects for compounds 1 and 2 were determined in vitro, with compound 1 demonstrating significant potency (EC50 value of 10 μM for both male and female worms), while 2 was inactive. Cytotoxicity assays against Vero cells revealed no toxicity for either compound (CC50 > 200 μM). Additionally, an in silico analysis was conducted using the SwissADME platform for 1, revealing that this natural sesquiterpene exhibited adherence to several ADME parameters and no PAINS violations. Finally, in vivo studies with S. mansoni-infected mice treated with compound 1 demonstrated a 44.0% reduction in worm burden, accompanied by decreases in egg production of 71.8% in feces and 69.5% in intestines. These findings highlight the potential of polygodial (1) as a promising prototype for schistosomiasis treatment.

Six new sesquiterpenes, including four eremophilane derivatives fureremophilanes A–D (1–4) and two acorane analogues furacoranes A and B (5 and 6), were characterized from the culture extract of the cold-seep derived fungus Furcasterigmium furcatum CS-280 co-cultured with autoclaved Pseudomonas aeruginosa QDIO-4. All the six compounds were highly oxygenated especially 2 and 3 with infrequent epoxyethane and tetrahydrofuran ring systems. The structures of 1–6 were established on the basis of detailed interpretation of 1D and 2D NMR and MS data. Their relative and absolute configurations were assigned by a combination of NOESY and single crystal X-ray crystallographic analysis, and by time-dependent density functional (TDDFT) ECD calculations as well. All compounds were tested the anti-inflammatory activity against human COX-2 protein, among which, compounds 2 and 3 displayed activities with IC50 values 123.00 µM and 93.45 µM, respectively. The interaction mechanism was interpreted by molecular docking.