Isolation and identification of neo-clerodane diterpenes from Ajuga remota by high-performance liquid chromatography

In vitro and in vivo antimalarial activity of green synthesized silver nanoparticles using Sargassum tenerrimum - a marine seaweed

Green nanotechnology has recently attracted a lot of attention as a potential technique for drug development. In the present study, silver nanoparticles were synthesised by using Sargassum tenerrimum, a marine seaweed crude extract (Ag-ST), and evaluated for antimalarial activity in both in vitro and in vivo models. The results showed that Ag-ST nanoparticles exhibited good antiplasmodial activity with IC50 values 7.71±0.39 µg/ml and 23.93±2.27 µg/ml against P. falciparum and P. berghei respectively. These nanoparticles also showed less haemolysis activity suggesting their possible use in therapeutics. Further, P. berghei infected C57BL/6 mice were used for the four-day suppressive, curative and prophylactic assays where it was noticed that the Ag-ST nanoparticles significantly reduced the parasitaemia and there were no toxic effects observed in the biochemical and haematological parameters. Further to understand its possible toxic effects, both in vitro and in vivo genotoxicological studies were performed which revealed that these nanoparticles are non-genotoxic in nature. The possible antimalarial activity of Ag-ST may be due to the presence of bioactive phytochemicals and silver ions. Moreover, the phytochemicals prevent the nonspecific release of ions responsible for low genotoxicity. Together, the bio-efficacy and toxicology outcomes demonstrated that the green synthesized silver nanoparticles (Ag-ST) could be a cutting-edge alternative for therapeutic applications.

Anti-Convulsant Activity of Soxhlet Leaf Extracts of Ajuga Integrifolia Buch.-Ham. Ex D.Don (Lamiaceae) in Mice

Background

The leaves of Ajuga integrifolia Buch.-Ham. ex D.Don (Lamiaceae) have long been used as an anti-convulsant remedy in Ethiopian traditional medicine. However, the evidence supporting their use is sparse in the literature. This study was conducted to add to the existing body of knowledge about the anti-convulsant activity of the plant.

Methods

The anti-convulsant activity of the extract was investigated in both acute (pentylenetetrazol [PTZ], 80 mg/kg; and maximal electroshock [MES]) and chronic (PTZ, 35 mg/kg) kindling seizure models. For the experimental paradigms, various doses of the extract (100, 200, and 400 mg/kg) were administered. Positive controls received sodium valproate (200 mg/kg) for the PTZ model and phenytoin (25 mg/kg) for the MES model. Parameters including the onset of clonus and duration of hindlimb tonic extension were recorded and compared with controls. Moreover, the total alkaloid, flavonoid, and phenol contents of the extracts were determined.

Results

Ethyl acetate extract produced a superior effect among all solvent extracts in both the PTZ and MES models. At all doses, it significantly delayed the mean onset of clonus (p<0.01) in the PTZ test compared to controls. It also significantly reduced (p<0.001) the mean duration of hindlimb tonic extension in the MES model. Treatment of mice with 200 mg/kg (p<0.01) and 400 mg/kg (p<0.001) of ethyl acetate extract significantly protected against PTZ-induced kindling compared to controls. The leaf was found to contain 10.002±0.119 mg atropine equivalent per gram of dry extract of alkaloids, 9.045±0.8445 mg quercetin equivalent per gram of dry extract of flavonoids, and 21.928±1.118 mg gallic acid equivalent per gram of dry extract of phenols.

Conclusion

This study indicated that the plant A. integrifolia has anti-convulsant activity in both acute and chronic models of seizure. This plant represents a potential source for the development of a new anti-epileptic drug for pharmacoresistant epilepsy.

Medicinal Plant Extracts Evaluated In Vitro and In Vivo for Antidiabetic Activities in Ethiopia: Bases for Future Clinical Trials and Related Investigations

Background

Diabetes mellitus (DM) is a metabolic disorder characterized by a persistent rise in the blood glucose level resulting from defects in cellular insulin function, secretion, or both, which affects millions of people every year. Several drawbacks have been stated with the use of marketed antidiabetic medicines such as drug resistance, adverse effects, toxicities, and even costs. Due to these several limitations, searching for novel antidiabetic medicines from medicinal plants (MPs) is becoming an active area of research. Therefore, MPs are exemplary sources of medicines with many accessible agents being obtained from them because numerous active constituents are isolated from them for direct use as pharmacological medicines or act as lead compounds. This paper was aimed to synthesize a concluding remark using in vitro and in vivo evaluations of extracts and fractions for antidiabetic potentials in Ethiopia, which can be used to direct future clinical trials and related investigations.

Method

So as to get data on the different investigations, publications related to experimental evaluations on animal diabetic models in Ethiopia were searched from databases, such as Google Scholar, Web of Science, Medline, PubMed, and Scopus using English key terms.

Results

In this paper, about 37 research findings based on data from various areas of Ethiopia published until the end of November 2020 were included. A total of 37 MP species extracts and fractions belonging to 19 families have been revealed in vitro or in vivo for potential antidiabetic activities. Crude extracts were carried out mostly by hydromethanolic whereas fractions were done mostly by chloroform. Leaves were the most commonly experimentally investigated plant part. Among the MP species experimentally studied, the most frequently used to treat DM in Ethiopia were Thymus schimperi Ronniger (Lamiaceae), Moringa stenopetala (Baker f.; Moringaceae), Ajuga remota Benth (Lamiaceae), and Datura stramonium Linn. (Solanaceae).

Conclusion

This paper gives aggregate evidences on the potential antidiabetic activities of MPs in Ethiopia. Antidiabetic MPs used in Ethiopia represent crucial input for the future development of novel antidiabetic drugs. To this end, more pharmacological and toxicological investigations need to be considered to prove the safety of constituents obtained from these MPs. Finally, we recommend upcoming research to ensure future success in the clinical study and development of novel medicines for DM treatment from these frequently evaluated MPs.

In vitro examination of anti-parasitic, anti-Alzheimer, insecticidal and cytotoxic potential of Ajuga bracteosa Wallich leaves extracts

This research study is mainly focused to evaluate the anti-parasitic, insecticidal, cytotoxic and anti-alzheimer potential of various leaf extracts of Ajuga bracteosa Wallich ex Bentham. 04 different extracts were prepared using solvent of different polarity to determine the best candidate for potent bioactivity i.e. n-hexane (NH), Ethyl acetate (EA), Ethanol (EL) and Chloroform (CH). Concentrations of each extracts were made specified for all activities. All extracts were exploited for broad range of biomedical applications including leishmaniasis, in vitro anti-Alzheimer, insecticidal and cytotoxic studies. Our results showed that A. bracteosa n-hexane extract was highly active against Leishmania Tropica with significant inhibition of 58 ± 1.61 for promastigote and 63 ± 2.29 for amastigote at 1000 μg/mL. Furthermore, promising anti-alzheimer activity acetylcholinesterase (AChE) 46 ± 0.83 and butrylcholineterase (BChE) 49 ± 1.17 was noted for n-hexane. The insecticidal potential of these extracts were test against five different insects (Rhyzopertha dominica, Trogoderma granarium, Tribolium castaneum, Sitophilus oryze, and Callosobruchus analis). The higest mortality rate of insecticidal activity was recorded by n-hexane followed by Ethyl acetate whereas ethanol extract was found to be less effective against all the test species. Significant cytotoxic potential of each plant sample against Artemia salina thus aware us for further detailed research to find out novel drugs. Based on our results we believe that Ajuga bracteosa could be used to develop as a potential botanical insecticide against different insect and pests, such as aphids as well as an excellent source for the compound isolation as anti-tumor agent.

Activity of Ajuga iva Extracts Against the African Cotton Leafworm Spodoptera littoralis

Control of the crop pest African cotton leafworm, Spodoptera littoralis (Boisduval), by chemical insecticides has led to serious resistance problems. Ajuga plants contain phytoecdysteroids (arthropod steroid hormone analogs regulating metamorphosis) and clerodanes (diterpenoids exhibiting antifeedant activity). We analyzed these compounds in leaf extracts of the Israeli Ajuga iva L. by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) and thin-layer chromatography (TLC), and their efficiency at reducing S.littoralis fitness. First and third instars of S. littoralis were fed castor bean leaves (Ricinus communis) smeared with an aqueous suspension of dried methanolic crude extract of A. iva phytoecdysteroids and clerodanes. Mortality, larval weight gain, relative growth rate and survival were compared to feeding on control leaves. We used '4',6-diamidino-2-phenylindole (DAPI, a fluorescent stain) and phalloidin staining to localize A. iva crude leaf extract activity in the insect gut. Ajuga iva crude leaf extract (50, 100 and 250 µg/µL) significantly increased mortality of first-instar S. littoralis (36%, 70%, and 87%, respectively) compared to controls (6%). Third-instar larval weight gain decreased significantly (by 52%, 44% and 30%, respectively), as did relative growth rate (-0.05 g/g per day compared to the relevant controls), ultimately resulting in few survivors. Crude leaf extract (250 µg/µL) reduced gut size, with relocation of nuclei and abnormal actin-filament organization. Ajug iva extract has potential for alternative, environmentally safe insect-pest control.

Isolation and Identification of Neo-Clerodane Diterpenes from Ajuga Nipponensis Makino

An extract of the aerial parts of Ajuga nipponensis Makino was examined by HPLC for neo-clerodane diterpenes. The suitability of reversed-phase HPLC for the semi-preparative fractionation of this extract was explored, resulting in the isolation of two new neo-clerodane diterpenes, which we have named ajuganipponin A, (12S)-1β,6α,19-triacetoxy-4α,18-epoxy-12-tigloyl-neo-clerod-13-en-15,16-olide (AJNP A, 1), and ajuganipponin B, (12S)-6α,19-diacetoxy-4α,18-epoxy-12-tigloyl-neo-clerod-13-en-15,16-olide (AJNP B, 6). In addition, ajugamarins A2 and F4, ajugamacrin B, ajugacumbin A and ajugatakasin A, were newly isolated compounds from A. nipponensis, along with the previously reported ajugamarins A1, B2 and L2 (ajugacumbin B). The structures of all the isolated compounds were unambiguously elucidated based on extensive NMR spectral studies (one and two-dimensional experiments) and their reversed-phase chromatographic behavior was established. The antifeedant activity of the isolated diterpenes against Spodoptera littoralis is also reported here.

Antidiabetic activity and phytochemical screening of extracts of the leaves of Ajuga remota Benth on alloxan-induced diabetic mice

Background

Ajuga remota Benth is traditionally used in Ethiopia for the management of diabetes mellitus. Since this claim has not been investigated scientifically, the aim of this study was to evaluate the antidiabetic effect and phytochemical screening of the aqueous and 70% ethanol extracts on alloxan-induced diabetic mice.

Methods

After acute toxicity test, the Swiss albino mice were induced with alloxan to get experimental diabetes animals. The fasting mean blood glucose level before and after treatment for two weeks in normal, diabetic untreated and diabetic mice treated with aqueous and 70% ethanol extracts were performed. Data were statistically evaluated by using Statistical Package for the Social Sciences software version 20. P-value <0.05 was considered statistically significant.

Results

The medium lethal doses (LD₅₀) of both extracts were higher than 5000 mg/kg, indicating the extracts are not toxic under the observable condition. Aqueous extracts of A.remota (300 mg/kg and 500 mg/kg body weight) reduced elevated blood glucose levels by 27.83 ± 2.96% and 38.98 ± 0.67% (P < 0.0001), respectively while the 70% ethanol extract caused a reduction of 27.94 ± 1.92% (300 mg/kg) & 28.26 ± 1.82% (500 mg/kg). Treatment with the antidiabetic drug, Glibenclamide (10 mg/kg body weight) lowered blood glucose level by 51.06% (p < 0.05). Phytochemical screening of both extracts indicated the presence of phenolic compounds, flavonoids, saponins, tannins, and steroids, which might contribute to the antidiabetic activity. The extracts, however, did not contain alkaloids and anthraquinones.

Conclusion

The aqueous extract (500 mg/kg) showed the highest percentage reduction in blood glucose levels and the ability of A. remota extracts in reducing blood glucose levels presumably due to the presence of antioxidant constituents such as flavonoids. The effect of the extract supported the traditional claim of the plant.

Chemical and pharmacological research on the plants from genus Ajuga

The genus

In vivo antiplasmodial activity and toxicological assessment of hydroethanolic crude extract of Ajuga remota

BACKGROUND

Malaria is one of the most life-threatening health problems worldwide and treatment has been compromised by drug resistance. Identifying lead molecules from natural products might help to find better anti-malarial drugs, since those obtained from natural sources are still effective against malarial parasites. This study aimed at investigating the in vivo antiplasmodial activity of crude extract of the leaves of Ajuga remota together with its safety in mice models.

METHODS

In vivo parasite growth inhibitory effect of crude extract was assessed in mice inoculated with Plasmodium berghei (ANKA strain). The in vivo antiplasmodial activity of the test extract was performed against early infection (4-day suppressive test), curative effect against established infection and prophylactic effect against residual infection. Acute and sub-acute toxicity were carried out according to OECD guidelines.

RESULTS

In vivo parasite growth inhibition effect of hydroethanolic crude extract of A. remota was evaluated at 30, 50 and 100 mg/kg dose levels. It suppressed parasitaemia by 77.34% at 100 mg/kg dose level in the 4-day test. In curative and prophylactic potential tests, it suppressed parasitaemia by 66.67 and 59.66% at 100 mg/kg dose level, respectively. In vivo toxicity tests revealed no toxicity. All parasitaemia suppressions were statistically significant at P < 0.05 as compared to the vehicle-treated group. The crude extract also prolonged survival time in a dose dependent manner.

CONCLUSIONS

The investigation results suggest that the leave extract of Ajuga remota possesses antimalarial activity.

A value-added use of volatile turpentine: antifungal activity and QSAR study of β-pinene derivatives against three agricultural fungi

22 derivatives from β-pinene were synthesized and their fungicidal activities against three pathogenic fungi were investigated. Studies showed that the introduction of an electron withdrawing group was favorable towards the fungicidal activity.

neo-Clerodane diterpenoids from Ajuga bracteosa

Different neo-clerodane diterpenoids were isolated from a dichloromethane extract of Ajuga bracteosa depending on the isolation procedure used, owing to the labile nature of these tetrahydrofurofuran derivatives. Under "hydroxyl-free" purification conditions, both clerodin- and dihydroclerodin-type diterpenes were obtained [four new compounds, ajubractins A-D (1-4), along with clerodin (5), 3-epi-caryoptin (6), ajugapitin (7), 14,15-dihydroclerodin (8), 3-epi-14,15-dihydrocaryoptin (9), ivain II (10), and 14,15-dihydroajugapitin (11)]. When methanol-water mixtures were used for a C18 reversed-phase prepurification procedure and for semipreparative HPLC, the new ajubractin E (12) was also isolated along with 3 and 8-11, as previously, but 7 was the only tetrahydrofurofuran derivative obtained. Epimeric (15R and 15S) mixtures were obtained instead of 14-hydro-15-hydroxyclerodin derivatives [15-hydroxyajubractin C (13), 14-hydro-15-hydroxyajugachin A (14), and 14-hydro-15-hydroxyajugapitin (15)], along with 15-epi-lupulin B (16). The structures of the new compounds were elucidated by NMR and MS data analysis and by comparison with values previously reported. Antifeedant activity against Spodoptera littoralis larvae was evaluated for the compounds obtained.