Botanical characterization of Guiera senegalensis leaves

Vibrational spectroscopic profiling of biomolecular interactions between oak powdery mildew and oak leaves

Oak powdery mildew, caused by the biotrophic fungus Erysiphe alphitoides, is a prevalent disease affecting oak trees, such as English oak (Quercus robur). While mature oak populations are generally less susceptible to this disease, it can endanger young oak seedlings and new leaves on mature trees. Although disruptions of photosynthate and carbohydrate translocation have been observed, accurately detecting and understanding the specific biomolecular interactions between the fungus and the leaves of oak trees is currently lacking. Herein, via hybrid Raman spectroscopy combined with an advanced artificial neural network algorithm, the underpinning biomolecular interactions between biological soft matter, i.e., Quercus robur leaves and Erysiphe alphitoides, are investigated and profiled, generating a spectral library and shedding light on the changes induced by fungal infection and the tree's defence response. The adaxial surfaces of oak leaves are categorised based on either the presence or absence of Erysiphe alphitoides mildew and further distinguishing between covered or not covered infected leaf tissues, yielding three disease classes including healthy controls, non-mildew covered and mildew-covered. By analysing spectral changes between each disease category per tissue type, we identified important biomolecular interactions including disruption of chlorophyll in the non-vein and venule tissues, pathogen-induced degradation of cellulose and pectin and tree-initiated lignification of cell walls in response, amongst others, in lateral vein and mid-vein tissues. Via our developed computational algorithm, the underlying biomolecular differences between classes were identified and allowed accurate and rapid classification of disease with high accuracy of 69.6% for non-vein, 73.5% for venule, 82.1% for lateral vein and 85.6% for mid-vein tissues. Interfacial wetting differences between non-mildew covered and mildew-covered tissue were further analysed on the surfaces of non-vein and venule tissue. The overall results demonstrated the ability of Raman spectroscopy, combined with advanced AI, to act as a powerful and specific tool to probe foliar interactions between forest pathogens and host trees with the simultaneous potential to probe and catalogue molecular interactions between biological soft matter, paving the way for exploring similar relations in broader forest tree-pathogen systems.

Toxicological evaluation of the leaves of Guiera senegalensis (J.F. Gme), Cassia occidentalis (Linn), and Ziziphus mauritiana (Lam)

Background

There is a renewed global interest in plant-based medicine in the last few decades as a result of affordability and efficacy of the form of medicine. However, the safety of many medicinal plants and plant preparations has not been determined. To this end, this study determined the safety of the methanol extracts of the leaves of Guiera senegalensis, Cassia occidentalis, and Ziziphus mauritiana, which are plants commonly used in plant medicine in Africa.

Results

Phytochemistry of the plants’ extracts showed alkaloids were the most abundant phytochemical in the extracts, followed by tannins, saponins, flavonoids, and glycosides, respectively. All the rats behaved normally at doses up to 2000 mg kg−1, while at 3000 mg kg−1, rats in C. occidentalis group developed breathing problems. At 5000 mg kg−1, C. occidentalis group showed convulsion, whereas Z. mauritiana and G. senegalensis rats displayed temporary weakness. After 60-day dosing, significant differences (p < 0.05) were observed in the liver enzymes (ALP, AST, ALT, TP, and ALB) of most of the test rats compared with the control. Kidney function test showed the Na+, K+, Cl−, urea, and creatinine of the test rats were reduced compared with the control, but only significant (p < 0.05) in a few of the parameters. Fatty metamorphosis, lymphocytic infiltration, and karyorrhexis were observed in the liver tissues of the treated rats, but not in the control.

Conclusion

These results show the plants are nontoxic at moderate doses, but could be injurious at high doses or if taken repeatedly for an extended period.

In vitro evaluation of novel antiviral activities of 60 medicinal plants extracts against hepatitis B virus

Currently, >35 Saudi Arabian medicinal plants are traditionally used for various liver disorders without a scientific rationale. This is the first experimental evaluation of the anti-hepatitis B virus (HBV) potential of the total ethanolic and sequential organic extracts of 60 candidate medicinal plants. The extracts were tested for toxicity on HepG2.2.15 cells and cytotoxicity concentration (CC₅₀) values were determined. The extracts were further investigated on HepG2.2.15 cells for anti-HBV activities by analyzing the inhibition of HBsAg and HBeAg production in the culture supernatants, and their half maximal inhibitory concentration (IC₅₀) and therapeutic index (TI) values were determined. Of the screened plants, Guiera senegalensis (dichloromethane extract, IC₅₀=10.65), Pulicaria crispa (ethyl acetate extract, IC₅₀=14.45), Coccinea grandis (total ethanol extract, IC₅₀=31.57), Fumaria parviflora (hexane extract, IC₅₀=35.44), Capparis decidua (aqueous extract, IC₅₀=66.82), Corallocarpus epigeus (total ethanol extract, IC₅₀=71.9), Indigofera caerulea (methanol extract, IC₅₀=73.21), Abutilon figarianum (dichloromethane extract, IC₅₀=99.76) and Acacia oerfota (total ethanol extract, IC₅₀=101.46) demonstrated novel anti-HBV activities in a time- and dose-dependent manner. Further qualitative phytochemical analysis of the active extracts revealed the presence of alkaloids, tannins, flavonoids and saponins, which are attributed to antiviral efficacies. In conclusion, P. crispa, G. senegalensis and F. parviflora had the most promising anti-HBV potentials, including those of C. decidua, C. epigeus, A. figarianum, A. oerfota and I. caerulea with marked activities. However, a detailed phytochemical study of these extracts is essential to isolate the active principle(s) responsible for their novel anti-HBV potential.

Foliar micro-morphology of Gasteria bicolor haw. (Asphodelaceae) from South Africa

BACKGROUND

The succulent genus, Gasteria, which comprises 16 species, is endemic to South Africa and has its main centre of distribution in the Savanna Region of the Eastern Cape. Whereas G. bicolor has been investigated phyto-chemically and pharmacologically, not much data concerning the anatomical and micro-morphological features can be found in literature.

MATERIALS AND METHODS

This study was undertaken, using light and scanning electron microscopy to obtain information on the micro-morphological features of this important medicinal plant to facilitate its identification and authentication. The elemental composition of the leaf was determined by energy dispersive X-ray spectroscopy (EDXS).

RESULTS

The epidermal cells are either hexagonal or pentagonal in form, and are compactly arranged with undulate anti-clinal cell walls. The epidermal cell width was approximately 50 µm. Stomata apertures are elliptical and the upper epidermis of the leaf has paracytic stomata which are slightly raised above the epidermal surface with 4 to 5 subsidiary cells surrounding each stoma. Based on the EDXS microanalysis, the mineral crystals present at the level of the mesophyll of G. bicolor were probably mixtures of calcium oxalate, calcium sulphate and silica.

CONCLUSION

The co-occurrence of aluminum suggests the potential role of the crystals in detoxification of aluminum and heavy metals, as reported previously.

Acaricidal properties of two extracts from Guiera senegalensis J.F. Gmel. (Combrataceae) against Hyalomma anatolicum (Acari: Ixodidae)

Laboratory test were carried out on eggs, larvae, nymphs and adults of Hyalomma anatolicum to determine the acaricidal activities of petroleum ether (PE) and crude ethanolic extracts (EE) from the leaves of Guiera senegalensis J.F. Gmel. (Combrataceae) using immersion method. Stock solutions, of 300 mg/ml (30%) of the each two extract, were prepared. Six two-fold serial dilutions each with three replicates were used. Both extracts, at the highest concentration 150 mg/ml (15%), induced 100% failure of hatching of the treated eggs. The concentrations of PE and EE that induced 50% inhibition of the hatchability (IC50) were 1.71 and 0.508%, respectively. In the larval immersion test (LIT), EE at 15% concentration caused complete mortality while the same concentration of PE resulted in 96% mortality. The mortalities increased with concentrations. There was a correlation between the mortalities and increased concentrations, the values of the linear correlation coefficient (r) for PE and EE were 0.93 and 0.79, and The LC50 and LC99 were 2.08 and 14.09, and 0.787 and 11.054, respectively. At the concentrations of 3.75%, 7.5% and 15%, PE inhibited the molting of the nymphs by 40, 55 and 65%, respectively, while EE induced 46.49, 64.3 and 71.4% inhibition, respectively. The effectiveness of the treatment against unfed adult females was assessed by measuring the feeding performance and egg production using adult immersion test (AIT). Although, there was no mortality in unfed adults, PE and EE inhibited feeding and egg-laying of the survived females by 35-100% and 6.16-100%, respectively. Our results indicated that G. senegalensis is a promising biocontrol candidate as an acaricidal agent against H. anatolicum.