Unveiling the Synergistic Effects of Phosphorus Fertilization and Organic Amendments on Red Pepper Growth, Productivity and Physio-Biochemical Response under Saline Water Irrigation and Climate-Arid Stresses.

In regions facing water scarcity and soil salinity, mitigating these abiotic stresses is paramount for sustaining crop production. This study aimed to unravel the synergistic effects of organic matter and phosphorus management in reducing the adverse effect of saline water for irrigation on red pepper (Capsicum annuum L.) production, fruit quality, plant physiology, and stress tolerance indicators. The study was carried out in the arid Tadla region of Morocco and involved two key experiments: (i) a field experiment during the 2019 growing season, where red pepper plants were subjected to varying phosphorus fertilizer rates (120, 140, and 170 kg of P2O5.ha-1) and saline water irrigation levels (0.7; 1.5; 3; and 5 dS.m-1); and (ii) a controlled pot experiment in 2021 for examining the interaction of saline water irrigation levels (EC values of 0.7, 2, 5, and 9 dS.m-1), phosphorus rates (30, 36, and 42 kg of P2O5.ha-1), and the amount of organic matter (4, 8, 12, and 16 t.ha-1). The field study highlighted that saline irrigation significantly affected red pepper yields and fruit size, although phosphorus fertilization helped enhance productivity. Additionally, biochemical markers of stress tolerance, such as proline and glycine betaine, along with stomatal conductance, were impacted by increasing salinity levels. The pot experiment showed that combining organic amendments and phosphorus improved soil properties and stimulated red pepper growth and root weight across all salinity levels. The integration of phosphorus fertilization and organic amendments proved instrumental for counteracting salinity-induced constraints on red pepper growth and yield. Nonetheless, caution is necessary as high salinity can still negatively impact red pepper productivity, necessitating the establishment of an irrigation water salinity threshold, set at 5 dS.m-1.

Influence of cutting time interval and season on productivity, nutrient partitioning, and forage quality of blue panicgrass (Panicum antidotale Retz.) under saline irrigation in Southern region of Morocco.

Salinity has become a major issue in various parts of the world negatively impacting agricultural activities and leading to diminished crop potential and lower yields. Such situation calls for urgent interventions such as adopting salt-tolerant crops to fill the gap in food and feed availability. Blue panicgrass (Panicum antidotale Retz.) is a promising salt-tolerant forage crop that has shown an appropriate adaptation and performance in the saline, arid, and desertic environments of southern Morocco. However, for obtaining a highest forage productivity with nutritional quality, optimization of the cutting interval is required. Thus, the objective of this study was to determine the optimal cutting time interval allowing high forage production and quality under high salinity conditions. This experiment was conducted over one entire year covering the summer and winter seasons. The effect of five cutting time intervals on selected agro-morphological traits, crop productivity, mineral nutrient accumulation, and forage quality of blue panicgrass in the region of Laayoune, southern Morocco. The finding of this study recommend that cutting blue panicgrass every 40 days maximized the annual fresh and dry forage yield as well as the protein yield, which reached 74, 22, and 2.9 t/ha, respectively. This study also revealed a significant effect of the season on both productivity and quality. However, forage yield declined during the winter and increased during the summer, while protein content increased during winter compared to summer. The mineral nutrient partitioning between shoots and roots, especially the K+/Na+ ratio, indicated that blue panicgrass has salt tolerance mechanism as it excluded sodium from the roots and compartmentalized it in the leaves. In conclusion, there is a potential of blue panicgrass on sustaining forage production under salt-affected drylands, as demonstrated by the response to two key questions: (a) a technical question to farmers for its adoption such as at which interval should blue panicgrass be harvested maximizing both forage yield and quality? And (b) a scientific question on how does blue panicgrass maintain high K+/Na+ ratio to cope with salinity stress?

Agro-morphological and biochemical responses of quinoa (Chenopodium quinoa Willd. var: ICBA-Q5) to organic amendments under various salinity conditions.

In the Sahara Desert, due to drought and salinity and poor soil fertility, very limited crop choice is available for the farmers to grow crops. Quinoa (Chenopodium quinoa Willd.) has shown promising under such conditions in the South of Morocco, a true representative site of Sahara Desert. Soil organic amendments have the potential to minimize negative effects of soil salinity and improve crop production. Thus, this study aimed to elucidate the impact of nine organic amendments on quinoa (var. ICBA-Q5) growth, productivity, and biochemical parameters under saline irrigation water application (4, 12, and 20 dS·m-1). Results of the experiment indicate a significant effect of organic amendments on major agro-morphological and productivity parameters. Biomass and seed yield tends to decrease with the rise of salinity level, and organic amendments have improved productivity compared to the non-treated control. However, salinity stress alleviation was assessed by determining pigments concentration, proline content, phenolic compounds, and antioxidant activity. Therefore, the action of organic amendments varies from one level of salinity to another. Furthermore, a remarkably significant decrease in total saponin content was reached due to the application of amendments even at high saline conditions (20 dS·m-1). The results demonstrate the possibility of enhancing the productivity of quinoa as an alternative food crop under salinity conditions by using organic amendments and improving the quality of grains (saponin reduction) during the pre-industrialization process.

Exploring the potential of mapped soil properties, rhizobium inoculation, and phosphorus supplementation for predicting soybean yield in the savanna areas of Nigeria.

Rapid and accurate soybean yield prediction at an on-farm scale is important for ensuring sustainable yield increases and contributing to food security maintenance in Nigeria. We used multiple approaches to assess the benefits of rhizobium (Rh) inoculation and phosphorus (P) fertilization on soybean yield increase and profitability from large-scale conducted trials in the savanna areas of Nigeria [i.e., the Sudan Savanna (SS), Northern Guinea Savanna (NGS), and Southern Guinea Savanna (SGS)]. Soybean yield results from the established trials managed by farmers with four treatments (i.e., the control without inoculation and P fertilizer, Rh inoculation, P fertilizer, and Rh + P combination treatments) were predicted using mapped soil properties and weather variables in ensemble machine-learning techniques, specifically the conditional inference regression random forest (RF) model. Using the IMPACT model, scenario analyses were employed to simulate long-term adoption impacts on national soybean trade and currency. Our study found that yields of the Rh + P combination were consistently higher than the control in the three agroecological zones. Average yield increases were 128%, 111%, and 162% higher in the Rh + P combination compared to the control treatment in the SS, NGS, and SGS agroecological zones, respectively. The NGS agroecological zone showed a higher yield than SS and SGS. The highest training coefficient of determination (R2 = 0.75) for yield prediction was from the NGS dataset, and the lowest coefficient (R2 = 0.46) was from the SS samples. The results from the IMPACT model showed a reduction of 10% and 22% for the low (35% adoption scenario) and high (75% adoption scenario) soybean imports from 2029 in Nigeria, respectively. A significant reduction in soybean imports is feasible if the Rh + P inputs are large-scaled implemented at the on-farm field and massively adopted by farmers in Nigeria.

Micropropagation of Opuntia and Other Cacti Species Through Axillary Shoot Proliferation: A Comprehensive Review.

Cacti are one of the most significant and diversified groups of angiosperms, distributed and cultivated globally, mostly in semi-arid, arid, and the Mediterranean climate regions. Conventionally, they are propagated by seeds or through vegetative propagation via rooted offshoots or grafting. However, these multiplication procedures remain insufficient for mass propagation. In vitro culture techniques are utilized to mass propagate endangered and commercial cacti species. These include somatic embryogenesis and plant regeneration through indirect or direct organogenesis. The latter is a promising tool for commercial clonal propagation of high-value species and has been successfully implemented for several species, such as Mammillaria, Hylocereus, Cereus, Echinocereus, and Ariocarpus. However, its success depends on explant type, basal nutrient formulation of culture medium, and types and concentrations of plant growth regulators. This study aimed to assess the potential of in vitro propagation methods applied to cacti species and discuss the different factors affecting the success of these methods. This study has also highlighted the insufficient work on Opuntia species for mass propagation through axillary buds' proliferation. The development of an efficient micropropagation protocol is thus needed to meet the supply of increasing demand of Opuntia species for human consumption as fruit, animal feed, and ecological restoration in semi-arid and arid zones.

How Does Quinoa (Chenopodium quinoa Willd.) Respond to Phosphorus Fertilization and Irrigation Water Salinity?

Soil salinity is a major problem in arid and semi-arid regions, causing land degradation, desertification, and subsequently, food insecurity. Salt-affected soils and phosphorus (P) deficiency are the common problems in the sub-Sahara, including the Southern region of Morocco. Soil salinity limits plant growth by limiting water availability, causing a nutritional imbalance, and imparting osmotic stress in the plants. The objective of this study was to determine the positive effects of P on growth and productivity and understand the major leaf mineral nutrient content of quinoa (Chenopodium quinoa Willd.) cv. "ICBA Q5" irrigated with saline water. A field experiment applying three salinity (Electrical Conductivity, EC) levels of irrigation water (ECw = 5, 12, and 17 dS·m-1) and three P fertilizer rates (0, 60, and 70 kg of P2O5 ha-1) were evaluated in a split-plot design with three replications. The experiment was conducted in Foum El Oued, South of Morocco on sandy loam soil during the period of March-July 2020. The results showed that irrigation with saline water significantly reduced the final dry biomass, seed yield, harvest index, and crop water productivity of quinoa; however, P application under saline conditions minimized the effect of salinity and improved the yield. The application of 60 and 70 kg of P2O5 ha-1 increased (p < 0.05) the seed yield by 29 and 51% at low salinity (5 dS·m-1), by 16 and 2% at medium salinity (12 dS·m-1), and by 13 and 8% at high salinity (17 dS·m-1), respectively. The leaf Na+ and K+ content and Na+/K+ ratio increased with irrigation water salinity. However, the leaf content of Mg, Ca, Zn, and Fe decreased under high salinity. It was also found that increasing P fertilization improved the essential nutrient content and nutrient uptake. Our finding suggests that P application minimizes the adverse effects of high soil salinity and can be adopted as a coping strategy under saline conditions.

Phosphorus Fertilization Enhances Productivity of Forage Corn (Zea mays L.) Irrigated with Saline Water.

Salinity is a major problem affecting crop production in many regions in the world including Morocco. Agricultural practices such as fertilization could be useful to overcome this problem and improve crop productivity. The objective of our study was to evaluate the combined effect of phosphorus fertilization and irrigation water salinity on growth, yield, and stomatal conductance of forage corn (Zea mays L.) cv. "Sy sincerro". Field experiments were carried out for two years testing four levels of irrigation water salinity (ECw = 0.7; 2, 4, and 6 dS·m-1) and three rates of phosphorus (105, 126, and 150 kg P2O5·ha-1) fertilization conducted in a split-plot design with three replications. The obtained results show that irrigation water salinity had a negative effect on all monitored parameters. For instance, the dry matter yield reduced by an average of 19.3 and 25.1% compared to the control under saline irrigation with an EC value equal to 4 and 6 dS·m-1, respectively. The finding also showed that phosphorus applications tend to increase root weight, root length, stem length, leaf stomatal conductance, grain yield and dry matter yield under salinity conditions. For example, the addition of phosphorus with a rate of 126 and 150 kg P2O5·ha-1 respectively improved dry matter yield by an average of 4 and 9% under low salinity level (ECw = 2 dS·m-1), by 4 and 15% under medium salinity (4 dS·m-1), and by 6 and 8% under a high salinity level (6 dS·m-1). Our finding suggests that supplementary P application could be one of the best practices to reduce the adverse effects of high salinity on growth and development of forage corn.

Land gradient and configuration effects on yield, irrigation amount and irrigation water productivity in rice-wheat and maize-wheat cropping systems in Eastern India.

Laser land levelling is expanding rapidly in the rice-wheat (RW) and maize-wheat (MW) systems of the Indo-Gangetic Plains of India and Pakistan. Current practice is to level to zero (0%) gradient, whereas a small gradient (e.g. 0.1%) is typically used in developed countries. Therefore, experiments were conducted in farmers' plots (~15 m x 40 m) in the Eastern Gangetic Plains to evaluate laser levelling with a 0.1% gradient in comparison with 0% and farmer levelling practice (FL). The study was conducted over two years in RW and MW systems. In the MW system, raised beds in plots lasered with 0% and 0.1% gradients were also evaluated. Laser levelling with 0% gradient significantly reduced irrigation amount and/or increased irrigation water productivity (WPi) in all crops/systems grown on the flat compared to FL except for wheat in the MW system. While there was a consistent trend for higher yield with a 0% gradient compared with FL, the differences were not significant in any crop/system. For the RW system, the results suggest no to marginal benefits in irrigation amount and WPi from levelling with a 0.1% gradient in comparison with 0% gradient. In that system, by far the bigger gains were from changing from FL to laser levelling with 0% gradient. This resulted in substantial reductions in irrigation amount, which greatly increased WPi in both crops (by ~40%), while yield was not affected. Rice grown with FL was not profitable, but lasering with 0% gradient significantly increased gross margin for rice, wheat and the total RW system. As for the RW system, levelling to 0% with a flat configuration significantly increased WPi of both crops in the MW system compared to FL, but by a lesser proportion. Raised beds significantly increased yield of maize by 8% (0.5 t ha-1), reduced irrigation amount by 20% (40 mm) and increased WPi by 34% (1.0 kg m-3) in comparison with the laser levelled flat plots. Gross margin of the MW system on beds was 17-20% higher than FL, and gross margin with beds on a 0.1% gradient was significantly higher than either gradient on the flat. The results suggest that the gains from levelling with a 0.1% gradient compared to 0% are marginal; however, this may change if the goal of consolidation of small farmer plots into larger fields becomes a reality provided there is a proportionate increase in irrigation flow rates, and ability to drain.

Assessing rice production sustainability performance indicators and their gaps in twelve sub-Saharan African countries.

The benchmarking and monitoring of rice production performance indicators are essential for improving rice production self-sufficiency, increasing profitability, reducing labor requirements, optimizing fertilizer inputs, engaging youths in rice production, and increasing the overall sustainability of smallholder rice production systems in countries in sub-Saharan Africa (SSA). In this paper, we quantified five sustainability performance indicators (grain yield, net profit, labor productivity, and nitrogen (N) and phosphorus (P) use efficiencies) to benchmark rice production systems in SSA. Data were collected between 2013-2014 from 2907 farmers from two rice production systems (irrigated and rainfed lowlands) across five agroecological zones (arid, semiarid, humid, subhumid and highlands) in 12 countries (Benin, Cameroon, Cote d'Ivoire, Ghana, Madagascar, Mali, Niger, Nigeria, Senegal, Sierra Leone, Tanzania and Togo). The exploitable gap for each indicator (the difference between the mean of 10 % highest-yielding farms and the mean-yielding farms) was calculated across the countries, the two production systems and agroecological zones. The mean yield varied widely between 2.5 to 5.6 t ha-1 and 0.6 to 2.3 t ha-1 in irrigated and rainfed lowlands, respectively, with an average yield of 4.1 and 1.4 t ha-1, respectively. Across the country-production system combinations, there were yield gaps of 29-69 %, profit gaps of 10-89 %, and labor productivity gaps reaching 71 %. Yield, profit, and labor productivity were positively correlated. They were also positively correlated with N and P fertilizer application rate, but not with N and P use efficiencies. Only between 34-44 % of farmers had desirable ranges in N- or P-use efficiencies in the two production systems. All sites for rainfed lowlands were characterized by low-yield and large gaps in yield, profit, and labor productivity, whereas irrigated lowlands in some countries (Madagascar, Mali, and Togo) have similar characteristics as rainfed ones. We conclude that there is an urgent need to disseminate precision nutrient management practices for optimizing nutrient use efficiency and enhancing rice performance indicators especially in rainfed lowlands as well as low-yielding irrigated lowlands. Furthermore, we propose recommendations for specific categories (i.e. farmer, rice production system, agroecological zone and country) to close performance indicator gaps and to allow the production at scale to achieve rice self-sufficiency in SSA.

Assessing alternative crop establishment methods with a sustainability lens in rice production systems of Eastern India.

Sustainability of rice production systems is a prime concern for Asia to maintain food security and to support economic growth. This gain in productivity not only depends on agricultural inputs but also depends on social and environmental factors. To address these emerging issues, new resource- and capital-efficient and profitable technologies have been introduced. The conventional method of rice production (puddling and manual transplanting, PTR) is considered as highly input intensive. As an alternative, dry direct seeded rice (DSR) using seed drill has been promoted to save labor and production costs compared with PTR. Similarly, machine transplanted rice (MTR) has been also considered and promoted in many rice growing countries of South and East Asia. Economic, environmental, and social performances of DSR and MTR (alternative rice establishment technologies) were compared to the PTR using Sustainable Rice Platform (SRP) defined 12 Performance Indicators (PIs) (version 1.0) as a gauge to measure their sustainability. For that, a household survey was conducted on 652 households in Odisha India during 2016. The gaps, i.e., the target to achieve better sustainability, were computed for most of the indicators from the difference between top 10th percentile and the population mean value of the indicator. The results indicated a yield gap of 1.35 t ha-1, a profit gap of $273 ha-1, labor productivity gap of 21 kg day-1, nitrogen (N) use efficiency gap of 22 kg grain kg-1 N, phosphorus (P) use efficiency gap of 105 kg grain kg-1 P, and water productivity gap of 0.00010 kg grain L-1 water in rice production systems in Odisha. Among the compared technologies, MTR results in the highest yield, profit, labor productivity, nitrogen-, phosphorus-use efficiency, and water productivity (at par), and is positive for children's welfare and the overall energy productivity, indicating better sustainability and has the potential to replace PTR. Direct seeded rice has the highest yield gap (1.57 t ha-1; 38%) but has the lowest production cost (can reduce the cost of production by $130 ha-1), and the highest greenhouse gas (GHG) reduction potential. SRP PIs are capable for assessing the sustainability of rice establishment technologies except for a few indicators, for example food safety and workers health and safety, which are more applicable to watershed and household level indicators, respectively. The SRP PIs provide scientific evidence and practical impetus for the selection and promotion of sustainable rice production technologies.

Tetra-acetylajugasterone a new constituent of Vitex cienkowskii with vasorelaxant activity.

Tetra-acetylajugasterone C (TAAC) was found to be one of the naturally occurring compounds of the Cameroonian medicinal plant Vitex cienkowskii which is responsible for a vasorelaxant activity of an extract of this plant. The evaluation of the underlying mechanisms for the relaxing effect of TAAC was determined using aortic rings of rats and mice. TAAC produced a concentration-dependent relaxation in rat artery rings pre-contracted with 1µM noradrenaline (IC50: 8.40µM) or 60mM KCl (IC50: 36.30µM). The nitric oxide synthase inhibitor l-NAME (100µM) and the soluble guanylate cyclase inhibitor ODQ (10µM) significantly attenuated the vasodilatory effect of TAAC. TAAC also exerted a relaxing effect in aorta of wild-type mice (cGKI(+/+); IC50=13.04µM) but a weaker effect in aorta of mice lacking cGMP-dependent protein kinase I (cGKI(-/-); IC50=36.12µM). The involvement of calcium channels was studied in rings pre-incubated in calcium-free buffer and primed with 1µM noradrenaline prior to addition of calcium to elicit contraction. TAAC (100µM) completely inhibited the resulting calcium-induced vasoconstriction. The same concentration of TAAC showed a stronger effect on the tonic than on the phasic component of noradrenaline-induced contraction. This study shows that TAAC, a newly detected constituent of Vitex cienkowskii contributes to the relaxing effect of an extract of the plant. The effect is partially mediated by the involvement of the NO/cGMP pathway of the smooth muscle but additionally inhibition of calcium influx into the cell may play a role.

Oxidative burst inhibitory and cytotoxic activity of constituents of the fruits of Odyendyea gabonensis.

The methanol extract of dried fruits of Odyendyea gabonensis afforded one new quassinoid [(-)-odyendanol (1)], one new canthin-6-one alkaloid [9-hydroxy-5-methoxycanthin-6-one (4)], and two new steroids [22E, 24R-stigmasta-5,22-diene-3,7-dione (7) and 22E,24R-stigmast-22-ene-3,7-dione (8)] along with fourteen known compounds. The structures of all compounds were established by analyzing the spectroscopic data. The ¹³C-NMR values of (-)-odyendene (2) and (-)-odyendane (3), as well as the single-crystal X-ray structure of 5-methoxycanthin-6-one (6) are also reported.The oxidative burst inhibitory activity of pure compounds 1-12 was determined by the chemoluminescence assay, and cytotoxic activities of compounds 2-6 against the human prostate cancer cell PC-3 line were evaluated. Compounds 1-6 exhibited a clear suppressive effect on the phagocytosis response upon activation with serum-opsonized zymosan in the range of IC50 = 0.9-2.0 µM versus ibuprofen with IC50 = 12.1 µM, while all canthin-6-one alkaloids (4-6) displayed moderate cytotoxic activity against the human prostate cancer cell PC-3 line, with IC50 values ranging from 13.5-15.4 µM versus doxorubicine with IC50 = 1.5 µM.

Bioactive ß-indoloquinazoline alkaloids from Oricia renieri.

Three new ß-indoloquinazoline alkaloids, orirenierine A (1), B (2) and C (4), together with eleven known compounds were isolated from the methanol extract of the stems of Oricia renieri. The structures of all compounds were determined by comprehensive analyses of their spectroscopic data and comparison with literature information. The alkaloids 9-11 were isolated for the first time from this genus. All compounds were tested for their activity against bacteria, fungi, and plant pathogen oomycetes using the paper disk agar diffusion assay. The agar diffusion test gave only low antimicrobial activities, corresponding to MICs > 1 mg/mL. However, compounds 1-4 and 11 exhibited a strong suppressive effect on phagocytosis response upon activation with serum opsonized zymosan in the range of IC(50) = 2.6-6.5 µM, while low cytotoxic activity against the human Caucasian prostate adenocarcinoma cell line PC-3 was observed with IC(50) values ranging from 22.9 to 39.4 µM.

Pentacyclic triterpenoids and ceramide mediate the vasorelaxant activity of Vitex cienkowskii via involvement of NO/cGMP pathway in isolated rat aortic rings.

ETHNOPHARMACOLOGICAL RELEVANCE: Vitex cienkowskii Kotschy & Peyritsch is a deciduous tree, prescribed by Cameroonian traditional healers as one of the most popular plant widely used in many disorders including cardiovascular diseases. The preliminary pharmacological studies carried out on Vitex cienkowskii showed its vasorelaxant activities on guinea-pig aortic rings. AIM OF THE STUDY: The present work evaluated the vasorelaxant activity of extract and isolated compounds from Vitex cienkowskii. MATERIALS AND METHODS: Rat aortic rings were used to evaluate the in vitro vascular effect of the extract. The antioxidant activity was determined by measuring the reduction of the free radical 1,1-diphenyl-1-picryl-hydrazyl (DPPH). RESULTS: Vitex cienkowskii induced significant relaxation in a concentration- and endothelium-dependent manner (EC(50)=12.12 µg/ml, CH(2)Cl(2)-MeOH, 1:1) and did not produce a vasorelaxant effect on contraction evoked by KCl (60 mM). In order to determine its mode of action, Vitex cienkowskii-induced relaxant effect was evaluated in the presence of indomethacin (10 µM), L-NAME (100 µM), ODQ (1 µM) and SQ22356 (100 µM). Relaxation was significantly blocked by L-NAME and ODQ. These results indicate that Vitex cienkowskii-mediated relaxation is endothelium dependent, probably due to NO release, and the consequent activation of vascular smooth muscle soluble guanylate cyclase (sGC), a signal transduction enzyme that forms the second messenger cGMP. Bio-guided study of Vitex cienkowskii allowed the isolation of the known pentacyclic triterpenoids and a ceramide. It is the first report of salvin A, maslinic acid and a ceramide from Vitex cienkowskii. The activity induced by these compounds indicated that they may be partly responsible for the vasorelaxant effect of the plant extract. A dose of 40 mg/kg of CH(2)Cl(2)-MeOH (1:1) extract administered intravenously induced a decrease of mean arterial pressure but did not affect the heart rate. Moreover the plant extracts were found to be highly active in the DPPH radical scavenging assay. CONCLUSION: Vitex cienkowskii extract possesses antioxidant property, vasorelaxing, and hypotensive effect linked to the endothelium related factors, where nitric oxide is involved.

Antiplasmodial constituents from the fruit pericarp of Pentadesma butyracea.

Bioassay-guided fractionation of the fruit pericarp of Pentadesma butyracea, using the antiplasmodial test, led to the isolation of a new xanthone, named pentadexanthone (1), together with six known compounds: cratoxylone (2), α-mangostin (3), 1,3,5-trihydroxy-2-methoxyxanthone (4), garcinone E (5), (-)-epicathechin (6), and lupeol (7). The structure of 1 was elucidated by spectroscopic data analysis. An antiplasmodial assay was performed with the isolates, in which compounds 1- 3 and 5 exhibited potent activity in vitro against Plasmodium falciparum chloroquine-resistant strain W2, with IC50 values below 3 µM.

Antimicrobial and antioxidant effects of phenolic constituents from Klainedoxa gabonensis.

Bioassay-guided fractionation of the methanol extract of the stem bark of Klainedoxa gabonensis Pierre ex Engl. (Irvingiaceae) afforded 12 compounds, namely, ellagic acid (1), ellagic acid 3,3'-dimethylether (2), gallic acid (3), methyl gallate (4), lupeol (5), ß-amyrin (7), erythrodiol (8), oleanolic acid (9), betulinic acid (6), hederagenin (10), bayogenin acid (11), and stigmasterol-3-O-ß-d-glucopyranoside (12). Compounds 1-3 and 7-12 were isolated for the first time from this genus. The structures were established on the basis of 1D/2D NMR experiments and mass spectrometric data. Crude extract, fractions (A, B, C and D) and pure compounds were tested for their antimicrobial activity using paper disk agar diffusion assay. The test delivered a range of low to high activities for phenolic compounds 1-4, low or missing activities for terpenoid compounds 5-11, and impressive very high antibacterial/antifungal values for two fractions C and D probably due to synergistic effects of compounds. The broth microdilution assay revealed MICs of 15.4-115.1 µg/mL for phenolic compounds, MICs higher than 1 mg/mL for terpenoids and MICs of 4.5-30.3 µg/mL for fractions C and D. The determination of the radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay gave high antioxidant values for the methanol extract and fraction D (IC(50) 10.45 and 5.50 µg/mL) as well as for the phenolic compounds 1-4 (IC(50) 45.50-48.25 mM) compared to the standard 3-t-butyl-4-hydroxyanisole (BHA) (IC(50) 44.20 mM).

Bioactive steroidal alkaloids from Sarcococca hookeriana.

Four new 5 alpha-pregnane-type steroidal alkaloids, hookerianamides L(1), M(2), N(3), and O(4), and a known N-formylchonemorphine (5) have been isolated by acid-base extraction of the dichloromethane extract of Sarcococca hookeriana. The structures of all compounds were determined with spectroscopic techniques and by comparison with literature data. All compounds displayed antileishmanial and antibacterial properties. Compounds 1, 4, and 5 were found to be more potent than standard pentamidine (IC (50) = 9.59 microg/mL) with respect to leishmanicidal activity. The minimum inhibitory concentration of most of the compounds against Bacillus subtilis, Streptococcus minor, and Streptococcus ferus was lower than that of the standard ampicillin.

Bioactive constituents of the stem bark of Beilschmiedia zenkeri.

Phytochemical investigation of the stem bark of Beilschmiedia zenkeri led to the isolation of four new methoxylated flavonoid derivatives, (2S,4R)-5,6,7-trimethoxyflavan-4-ol (1), (2S,4R)-4,5,6,7-tetramethoxyflavan (2), beilschmieflavonoid A (3), and beilschmieflavonoid B (4), together with seven known compounds. The structures of 1-4 were established by spectroscopic methods, and their relative configurations confirmed by X-ray crystallographic and CD analysis. The isolated compounds were evaluated in vitro for their antibacterial activity against three strains of bacteria, Pseudomonas agarici, Bacillus subtilis, and Streptococcus minor, and for their antiplasmodial activity against Plasmodium falciparum, chloroquine-resistant strain W2.

Nepetanal and nepetanoate: a new diterpene aldehyde and a benzene derivative ester from Nepeta juncea.

One new tricyclic clerodane type diterpene aldehyde nepetanal (1) and one new benzene derivative nepetanoate (2) have been isolated from a plant Nepeta juncea together with two known compounds oleanolic acid (3) and ursolic acid (4). The structures of the isolated compounds were elucidated by means of modern spectroscopic techniques and comparison with literature data.

Antibacterial endiandric acid derivatives from Beilschmiedia anacardioides.

Three endiandric acid derivatives, beilschmiedic acids A, B and C were isolated from the stem bark of Beilschmiedia anacardioides together with the known beta-sitosterol. Their structures were established by means of modern spectroscopic techniques. The relative configuration of compound 1 was determined by single crystal X-ray analysis. The antibacterial activities of compounds A,B,C were evaluated in vitro against five strains of microbes. Compound C showed strong activity against Bacillus subtilis, Micrococcus luteus and Streptococcus faecalis (MICs below 23 microM). This Compound was more active than the reference antibiotic ampicillin against B. subtilis and M. luteus.