Comparative analysis on bioactivity against three stored insects of Ligusticum pteridophyllum Franch. rhizomes essential oil and supercritical fluid (SFE-CO2) extract.

In order to develop more environmentally benignant insecticides, the Ligusticum pteridophyllum Franch. rhizomes essential oil and supercritical fluid (SFE-CO2) extract were obtained by two published techniques, hydrodistillation and SFE-CO2. The chemical components of this two tested samples were identified by using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID). Repellent activity and contact toxicity of the obtained samples and myristicin against the adults of Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma serricorne (Coleoptera: Anobiidae), and Liposcelis bostrychophila (Psocoptera: Liposcelididae) were compared. Nineteen components were identified in the SFE-CO2 extract. Twelve components were identified in the L. pteridophyllum rhizomes essential oil. SFE-CO2 extract exhibited higher contact toxicity against T. castaneum, L. serricorne, and L. bostrychophila (LD50 = 69.60 µg/adult, 14.58 µg/adult, and 1.69 µg/cm2, respectively) than that of L. pteridophyllum rhizomes essential oil (LD50 = 87.99 µg/adult, 89.82 µg/adult, and 7.87 µg/cm2, respectively). Besides, myristicin (LD50 = 36.46 µg/adult) showed superior contact toxicity against T. castaneum than that of the L. pteridophyllum rhizomes essential oil and SFE-CO2 extract. It possessed potentially practical significance to develop L. pteridophyllum rhizomes into plant pesticide or repellent agent for these stored insect controls. Graphical abstract .

Metabolomic study of raw and bran-fried Atractylodis Rhizoma on rats with spleen deficiency.

Atractylodis Rhizoma, a classical Chinese medicine, exhibits unambiguous therapeutic effect on spleen deficiency in China for decades. The aim of the present study was to explore the different effects on the composition and level of endogenous metabolites in rats with spleen deficiency after oral administration of raw and bran-fired Atractylodis Rhizoma, and to explain the mechanism of pharmacodynamic enhancement of the bran-fried Atractylodis Rhizoma from the perspective of metabolomics. With this purpose, spleen deficiency model was established by diet, excessive fatigue and bitter cold diarrhea. Then, Enzyme-linked immunosorbent assay (ELISA) was used to determine the contents of vasoactive intestinal peptide (VIP), Somatostatin (SS), substance P (SP) and succinodehydrogenase (SDH) in rats of each group, and to compare the contents of VIP, SS, SP and SDH among groups. UHPLC-Q-TOF-MS based metabolomics was adopted to analyze the plasma from spleen deficiency rats and control rats. Principle component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were utilized to identify differences of metabolic profiles in rats among the control group and the model group；The OPLS-DA were used to analyze the effects of raw and bran-fried Atractylodis Rhizoma on the same metabolites. The results showed that compared with the control group, the contents of VIP, SS, SP and SDH in the plasma of model group decreased, which proved the success of the model group. Compared with model group, the contents of VIP, SS, SP and SDH in the plasma of raw and bran-fried Atractylodis Rhizoma increased, and the effect of bran-fried Atractylodis Rhizoma was better than that of raw Atractylodis Rhizoma. Metabolomics results showed that seventeen different metabolites of spleen deficiency were screened out in the plasma of rats with spleen deficiency compared with the control group. Among them, Nicotinic acid, Dihydrofolic acid, Pantetheine 4'-phosphate and Photophatidylcholine (PC) were the metabolites significantly associated with spleen deficiency, and bran-fried Atractylodis Rhizoma had better intervention and regulation. Through the analysis of metabolic pathways related to these different metabolites of spleen deficiency, and primarily involved in glucosamine metabolism, one carbon pool by folate and so on. This study showed that Atractylodis Rhizoma could provide satisfactory therapeutic effects on spleen deficiency and metabolomics study can be utilized to further understand the molecular mechanisms.

Toxicity and repellent activity of essential oil from Mentha piperita Linn. leaves and its major monoterpenoids against three stored product insects.

The essential oil (EO) from leaves of Mentha piperita was extracted by hydrodistillation. Twenty-one chemical components, accounting for 97.5% of the total oil, were determined by GC-MS and GC-FID. The major chemical components included menthol (41.6%), L-menthone (24.7%), isomenthol (6.3%), and limonene (5.0%). The bioactivity of the obtained EO and its two major components against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults were evaluated by fumigation, contact, and repellent activity bioassay. The EO showed significant fumigation and contact toxicity against T. castaneum (LC50 = 18.1 mg/L air and LD50 = 2.9 µg/adult, respectively), L. serricorne (LC50 = 68.4 mg/L air and LD50 = 12.6 µg/adult, respectively), and L. bostrychophila (LC50 = 0.6 mg/L air and LD50 = 49.8 µg/adult, respectively) adults. Meanwhile, the repellent effect of the EO on T. castaneum and L. serricorne adults was comparable to that of the positive control at the highest tested concentration. Menthol and L-menthone were two major components in total oil. Among them, L-menthone exhibited significant insecticidal activity on target insects, and menthol showed notable repellent effects. The results indicated that the EO of M. piperita leaves and two tested components have potential to be developed as natural insecticides and repellents for the control of stored product insect pests. Graphical abstract.