Chemotaxonomy of Gonospermum and related genera

Structure-Based Molecular Networking for the Discovery of Anti-HBV Compounds from Saussurea lappa (Decne.) C.B Clarke

It is a crucial to find target compounds in natural product research. This study presents a concept of structure-guided isolation to find candidate active molecules from herbs. We establish a process of anti-viral sesquiterpene networking. An analysis of the networking suggested that new anti-HBV sesquiterpene may be attributable to eudesmane-, guaiane-, cadinane-, germacane- and bisabolane-type sesquiterpenes. In order to evaluate the efficiency of the structure-based molecular networking, ethanol extract of Saussurea lappa (Decne.) C.B Clarke was investigated, which led to the isolation of two guaiane-type (1 and 14), ten eudesmane-type (2–5 and 8–13), two chain (6 and 7) and one germacrane-type (15) sesquiterpenes, including seven new ones, lappaterpenes A–G (1–7), which are reported on herein. The absolute configurations of the new compounds were established by coupling constants, calculated ECD and ROESY correlations, as well as comparisons of optical rotation values with those of known compounds. The absolute configuration of compound 2 was further confirmed by X-ray diffraction. Compounds 1–15 were evaluated for their potency against hepatitis B virus. Compounds 4, 6, 7 and 9 showed effect on HBsAg with inhibition ratios of more than 40% at 30 μM concentrations. Compounds 14 and 15 inhibited HBsAg secretion with the values of IC₅₀ 0.73 ± 0.18 and 1.43 ± 0.54 μM, respectively. Structure-based molecular networking inspired the discovery of target compounds.

Structural characterization of bioactive compounds in Cotula cinerea extracts by ultra-high-performance liquid chromatography with photodiode array and high-resolution time-of-flight mass spectrometry detectors

RATIONALE

Cotula cinerea of the Asteraceae family is a traditional Moroccan plant with various biological activities such as analgesic, cytotoxic and antioxidant effects which are often related to the presence of secondary metabolites. The present work aims to screen and identify the main phytochemicals compounds of Cotula cinerea extracts.

METHODS

A method was developed that coupled a rapid and simple ultra-high-performance liquid chromatography system with both photodiode array and high-resolution time-of-flight mass spectrometry detectors (UHPLC-PDA/TOF-HRMS) for the identification of the main secondary metabolites of three investigated extracts (hexane, AcOEt and n-BuOH).

RESULTS

A total of 30 phytocomponents pertaining to phenolic compounds and terpenoids have been detected, identified and quantified. Among these were previously reported free and conjugated coumaric and caffeic acids along with free and conjugated flavones and flavonols with kaempferol, quercetin, luteolin and apigenin aglycones. In addition, sulfated flavonoids were identified in the investigated extracts and are reported in this work for the first time in Cotula cinerea. The obtained results have been discussed in relation to the biological activities of the corresponding extracts.

CONCLUSIONS

This study proposed a practical strategy for rapidly screening and identifying secondary metabolites of Cotula cinerea and provided new information on the phytochemicals of this Saharan plant. This work has therefore provided useful results for further pharmacological studies and the design of new drugs based on this species and will facilitate the utilization of Cotula cinerea in the clinic and its safety evaluation. It is also hoped that the information presented here might stimulate further studies that will possibly lead to development of therapeutic agents from this plant.

Phytotoxicity of secondary metabolites isolated from Flourensia oolepis S.F.Blake

The aim of this study was to isolate the active principles of Flourensia oolepis S.F.Blake (Asteraceae), which completely inhibited the germination of Raphanus sativus seeds at 10 mg/ml. Flavanone pinocembrin and sesquiterpene ilicol, were isolated by bioassay-guided fractionation. They were active both against monocot and dicot seeds. Pinocembrin was the most active compound, with an IC50 (germination) value of 0.24, 3.40, 3.28, and 3.55 mM against Panicum miliaceum, Avena sativa, Lactuca sativa, and R. sativus, respectively; ilicol, however, exhibited IC50 (germination) values of 0.67, 2.73, 5.25, and 9.66 mM for the same species, respectively. Pinocembrin and ilicol inhibited root growth and showed IC50 (root growth) values of 0.199, 14.68, 8.05, 7.69 mM, and 1.22, 2.90, 7.35, 8.07 mM, against P. miliaceum, A. sativa, L. sativa, and R. sativus, respectively. Pinocembrin and ilicol reduced Allium cepa cell division without chromosome aberrations.

A chemotaxonomic study of endemic species of genus Tanacetum from the Canary Islands

Aerial parts of Tanacetum oshanahanii collected at "Jardín Canario Viera y Clavijo", Tanacetum ptarmiciflorum collected at Los Moriscos (Tejeda), and Tanacetum ferulaceum var. latipinnum collected at Anden Verde (Agaete) in Gran Canaria, Canary Islands, afforded three sesquiterpenes related to nerolidol and six sesquiterpene lactones whose structures were established on the basis of their spectroscopic data and chemical transformations. In this work we show that this type of sesquiterpene lactones could be used as chemotaxonomic markers. A series of sesquiterpene lactones described in this paper were assessed for cytotoxicity against HL-60 and U937 cancer cell lines. The derivatives 106a and 98a displayed cytotoxic properties showing IC50 values between 5 and 11 μM. Furthermore, we demonstrated that these selected sesquiterpene lactones induce apoptotic cell death in human leukemia cells through a mechanism that involves activation of multiple caspases and moreover cell death was found to be associated with the release of cytochrome c.