Cyperus rotundus L.: Invasive weed plant with insecticidal potential against Aphis craccivora Koch and Planococcus lilacinus (Cockerell).

Cyperus rotundus L. is a widely distributed invasive weed plant with vast traditional medicinal uses. Herein, the methanolic root extract of C. rotundus and its fractions (n-hexane, chloroform, n-butanol, and aqueous) were evaluated for insecticidal activity against nymphs of Aphis craccivora Koch and crawlers of Planococcus lilacinus (Cockerell) to find promising lead (s). In contact topical assay, among extract/fractions, n-hexane fraction exhibited more toxicity against A. craccivora (LD50 = 1.12 µg/insect) and P. lilacinus (LD50 = 0.94 µg/insect). The chemical analysis of n-hexane fraction revealed a volatile composition similar to that of the essential oil (EO) of C. rotundus roots. Hence, EO was extracted using water and deep eutectic solvents (DESs) as cosolvent, which revealed enhancement in EO yield (from 0.28 to 0.46% w/w) on implementing DESs. A total of 35 diverse volatile metabolites were identified in all EO samples, accounting for 85.0 to 91.8% of chemical composition, having cyperotundone, cyperene mustakone, isolongifolen-5-one, boronia butenal as major constituents. The EO obtained with DES-7 [choline chloride: ethylene glycol (1:4)] and DES-6 [choline chloride: lactic acid (1:3)] were found effective against A. craccivora (LD50 = 0.62-0.87 µg/insect) and P. lilacinus (LD50= 0.59-0.67 µg/insect) after 96 h. NMR analysis of EO revealed cyperotundone as a major compound, which was isolated along with cyperene and cyperene epoxide. All the molecules were found effective against P. lilacinus, whereas against A. craccivora cyperotundone, cyperene and cyperene epoxide showed promising toxicity (LD50 = 0.74-0.86 µg/insect). Extract/fractions, EO, and isolated molecules showed a significant reproductive inhibition rate of A. craccivora at higher concentrations. All the tested concentrations of cyperotundone showed significant inhibition of acetylcholinesterase (AChE) and glutathione-S-transferase (GST) in A. craccivora and P. lilacinus. Based upon the present study, C. rotundus can be recommended to control targeted insects in the greenhouse/field conditions after performing bio-efficacy and phytotoxicity studies.

Antiplasmodial diterpenoid alkaloid from Aconitum heterophyllum Wall. ex Royle: Isolation, characterization, and UHPLC-DAD based quantification.

ETHNOPHARMACOLOGICAL RELEVANCE: Aconitum heterophyllum Wall. ex Royle is a traditionally important medicinal plant having numerous therapeutic actions as documented in Ayurveda. This plant is traditionally known for combating worm infestation, fever, respiratory tract disease, vomiting, diarrhoea, diabetes, skin disorders, anaemia, and joint disorders. Further, it has been used alone and in combination with other plants to prepare various anti-malarial formulations. However, there is no report on the assessment of its anti-plasmodial activity, and the metabolite(s) responsible for this activity. AIM OF THE STUDY: The main aim of this study was to conduct phytochemical investigation of A. heterophyllum roots for the preparation of extract, fractions, and isolation of pure molecules to identify active fractions/molecules responsible for the anti-plasmodial activity, and development of UHPLC-DAD based analytical method which can be used for the quantification of marker compounds in the extracts and fractions. MATERIALS AND METHODS: Hydroalcoholic extract (1:1 v/v) and fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and water) were prepared from the dried powdered roots of A. heterophyllum. Fractions were further subjected to silica gel column chromatography to isolate pure specialized secondary metabolites from this plant. All extracts, fractions, and pure molecules were evaluated against the chloroquine resistant Pf INDO and chloroquine sensitive Pf3D7 strains in culture for calculating their IC50 values. UHPLC-DAD based analytical method was also developed for the first time for the quantification of marker compounds and quality assessment of this commercially important Himalayan medicinal plant. RESULTS: Phytochemical investigation of A. heterophyllum root led to the isolation of six specialized metabolites viz. 2-O-cinnamoyl hetisine (1), atisinium (2), 4-oxabicyclo [3.2.2] nona-1(7),5,8-triene (3), atisinium cinnamate (4), aconitic acid (5), and atisinium formate (6). Compound 1 is a new hetisine type diterpenoid alkaloid, compounds 4 and 6 are new counter ionic forms observed with atisinium ion, and compound 3 is being reported for the first time from this genus. Chloroform fraction was found to be the most active with IC50 (µg/mL) 1.01 (Pf INDO) and 1.32 (Pf3D7). The molecule 2-O-cinnamoyl hetisine (1), a new diterpenoid alkaloid isolated from chloroform fraction, showed promising antiplasmodial activities with IC50 (µM) 1.92 (Pf INDO) and 10.8 (Pf 3D7). The activity of chloroform fraction was further validated by the developed UHPLC-DAD based method as the quantity of 2-O-cinnamoyl hetisine (1) was higher in the chloroform fraction (≅200 mg/g) than in all other fractions (<7 mg/g). Atisinium (2) and 2-O-cinnamoyl hetisine (1) were found to be the main marker compounds of this plant based on quantity and antiplasmodial activity, respectively. CONCLUSION: This study provides the scientific rationale for the traditional use of this plant in treating malaria. Further, this study revealed that the anti-malarial potential of this plant might be due to the presence of diterpenoid alkaloids.