Composition of essential oil from the bark and leaves of two morphotypes of Salmea scandens (Asteraceae), a medicinal plant in Oaxaca, Mexico.

The chemical composition of the essential oils (EOs) from leaves and bark of two morphotypes, white (WM) and black (BM) of Salmea scandens obtained by microwave-assisted extraction (MAE) were analyzed by GC-MS. The major components of the bark EOs were aliphatic hydrocarbons (38.0% in WM, 48.6% in BM) and oxygenated sesquiterpenes (27.6% in WM, 11.3% in BM); in leaves EOs major components were oxygenated sesquiterpenes (43.9% in WM, 45.7% in BM) and oxygenated aliphatics (13.7% in WM, 1.1% in BM) stood out. Nine components have been reported to have antimicrobial and anti-inflammatory potential. The agglomerative hierarchical clustering and principal component analysis confirmed the variability of the EOs. These results suggest that WM may have a better therapeutic effect for treating infectious and inflammatory processes in traditional medicine.

Dataset on dynamics of Coronavirus on Twitter.

In this data article, we provide a dataset of 8,982,694 Twitter posts around the coronavirus health global crisis. The data were collected through the Twitter REST API search. We used the rtweet R package to download raw data. The term searched was "Coronavirus" which included the word itself and its hashtag version. We collected the data over 23 days, from January 21 to February 12, 2020. The dataset is multilingual, prevailing English, Spanish, and Portuguese. We include a new variable created from other four variables; it is called "type" of tweets, which is useful for showing the diversity of tweets and the dynamics of users on Twitter. The dataset comprises seven databases which can be analysed separately. On the other hand, they can be crossed to set other researches, among them, trends and relevance of different topics, types of tweets, the embeddedness of users and their profiles, the retweets dynamics, hashtag analysis, as well as to perform social network analysis. This dataset can attract the attention of researchers related to different fields on knowledge, such as data science, social science, network science, health informatics, tourism, infodemiology, and others.

Chemical composition of the essential oil from Ageratina jocotepecana and its repellent effect on drywood termite incisitermes marginipennis / Composición química del aceite esencial de Ageratina jocotepecana y su efecto repelente en termitas de madera seca incisitermes marginipennis

Essential oils obtained from new plant species with metabolomes unexplored or poorly known are a natural resource to find molecules with deterrent (irritant) effect. The aim of this study was to evaluate the chemical composition and the termite repellent activity of the essential oils from Ageratina jocotepecana. The repellent effect was determined by the pine drywood termite Incisitermes marginipennis behavior of to sense the contact of the tunnel wall in the wooden colony in the presence of an irritant obstacle caused by essential oils. Gas chromatographic analysis of the essential oils from flower, leaf, and stem showed quantitative and qualitative differences in components. Twenty-eight volatile components were identified by their mass spectra (MS). beta-caryophyllene, carvacrol, spathulenol, and terpinen-4-ol were the four major components, of them in relation 0.1 M citronellol, the 0.1 M carvacrol was the best repellent of the termite. Essential oils from A. jocotepecana exhibited a termite repellent effect due to their major components. Additionally, more research about the termite repellent action of carvacrol is still needed.

Los aceites esenciales obtenidos de nuevas especies de plantas con metabolomas inexplorados o poco conocidos son un recurso natural para encontrar moléculas con efecto disuasivo (irritante). El propósito del estudio fue evaluar la composición química de los aceites esenciales de Ageratina jocotepecana y su actividad repelente de termitas. El efecto repelente fue determinado por el comportamiento de las termitas de la madera seca de pino Incisitermes marginipennis de sentir el contacto de la pared del túnel en la colonia de madera en la presencia de un obstáculo irritante causado por los aceites esenciales. El análisis de cromatografía de gases de los aceites esenciales de flores, hojas y tallo mostró diferencias cuantitativas y cualitativas en componentes. Veintiocho componentes volátiles fueron identificados por sus espectros de masas (MS). beta-cariofileno, carvacrol, spathulenol y terpinen-4-ol fueron los cuatro componentes mayoritarios, de ellos en relación con 0,1 M citronelol el control positivo, el carvacrol 0,1 M fue el mejor repelente de la termita. Además, más investigación sobre la acción repelente de termitas de carvacrol se necesita realizar.

Absolute configuration of (13R)- and (13S)-labdane diterpenes coexisting in Ageratina jocotepecana.

Chemical investigation of the hexanes extracts of Ageratina jocotepecana afforded (-)-(5S,9S,10S,13S)-labd-7-en-15-oic acid (1), methyl (-)-(5S,9S,10S,13S)-labd-7-en-15-oate (2), (+)-(5S,8R,9R,10S,13R)-8-hydroxylabdan-15-oic acid (3), and (-)-(5S,9S,10S,13Z)-labda-7,13-dien-15-oic acid (5). The coexistence of (13R)- and (13S)-labdanes in this member of the Asteraceae family was demonstrated by vibration circular dichroism measurements of ester 2 and methyl (+)-(5S,8R,9R,10S,13R)-8-hydroxylabdan-15-oate (4) in comparison to the DFT B3LYP/DGDZVP-calculated spectra. In addition, transformation of 1 and 3 with HClO4 in MeOH yielded epimeric methyl (+)-(5S,10S,13S)-labd-8-en-15-oate (6) and methyl (+)-(5S,10S,13R)-labd-8-en-15-oate (7), respectively, confirming the presence of C-13 epimers in this plant. Diterpene 1 showed remarkable antibacterial activity against Bacillus subtilis (MIC 0.15 mg/mL) and Staphylococcus aureus (MIC 0.78 mg/mL), while diterpene 3 exhibited moderate activities against the same organisms.