Phytonutritional compounds and antioxidant activity of eight new edible flowers

In the last years, special attention has been given to the nutritional properties of food, and the edible flowers (EFs) represent an uncommon fresh product to characterise, with the aim to explore new species with peculiar aesthetic and the aromatic features. This work investigated some nutritional properties of eight new EFs, such as Begonia boliviensis A.DC. (pink and white varieties), Dahlia pinnata Cav., Salvia farinacea Benth., S. × jamensis J.Compton, S. 'Purple Queen' Tulbaghia simmleri Beauv. 'Alba', T. violacea Harv. 'Alba', chosen for their different colours and corolla morphologies. Primary and secondary metabolites have been determined. The highest protein content was found in T. violacea 'Alba' and D. pinnata. The Salvia species showed the highest soluble sugar content. The two Tulbaghia species were notable for hexose and ascorbic acid content. D. pinnata showed the highest polyphenols, flavonoids and carotenoid content, with the highest antiradical activity.

Identification of a regiospecific S-oxygenase for the production of marasmin in traditional medicinal plant Tulbaghia violacea

Marasmin [S-(methylthiomethyl)-L-cysteine-4-oxide] is a pharmaceutically valuable sulfur-containing compound produced by the traditional medicinal plant, Tulbaghia violacea. Here, we report the identification of an S-oxygenase, TvMAS1, that produces marasmin from its corresponding sulfide, S-(methylthiomethyl)-L-cysteine. The amino acid sequence of TvMAS1 showed high sequence similarity to known flavin-containing S-oxygenating monooxygenases in plants. Recombinant TvMAS1 catalyzed regiospecific S-oxygenation at S4 of S-(methylthiomethyl)-L-cysteine to yield marasmin, with an apparent K _m value of 0.55 mM. TvMAS1 mRNA accumulated with S-(methylthiomethyl)-L-cysteine and marasmin in various organs of T. violacea. Our findings suggest that TvMAS1 catalyzes the S-oxygenation reaction during the last step of marasmin biosynthesis in T. violacea.

The effect of Beauveria bassiana inoculation on plant growth, volatile constituents, and tick (Rhipicephalus appendiculatus) repellency of acetone extracts of Tulbaghia violacea

Aim

The purpose of the present study was to evaluate the effects of Beauveria bassiana (Hypocreales) inoculum on plant growth, volatile constituents, and tick repellency of the extracts of Tulbaghia violacea (Amaryllidaceae).

Materials and Methods

Eight-week-old potted seedlings of T. violacea were each inoculated with conidia of B. bassiana (strain SM3) suspended at a concentration of 1×10⁶ conidia mL^-1. Tissue colonization by fungal conidia was assessed after 3 weeks. Plant growth, volatile constituents, and tick repellency were assessed after 12 weeks post-treatment.

Results

B. bassiana conidia successfully colonized leaf and root tissues of T. violacea. The growth of fungal hyphae out of the leaf and root sections occurred in 75% and 91.6% of plants, respectively. Inoculation of the plants with B. bassiana significantly (p<0.05) influenced root length and plant height but did not have substantial effects on weights and leaf number of T. violacea. While the fungus did not have significant effects on overall number of the volatile chemical constituents, significant variations in the quantity (area ratio) were observed in at least four compounds that were detected. In the tick repellency bioassay, high concentration (20 w/v%) of acetone extract from fungus-exposed plants produced the least repellent effect on Rhipicephalus appendiculatus larvae (Ixodidae), while at lower concentrations (5 w/v% and 10 w/v%) of acetone extracts of T. violacea, tick repellent activity of the extract of the fungus treatment was significantly improved and was comparable to commercial N,N-Diethyl-m-toluamide and the other treatments.

Conclusion

Experimental fungal inoculation positively influenced plant growth in height and root length and tick (R. appendiculatus) repellency of acetone extracts of T. violacea at a concentration of 10 w/v% compared to the control treatment.

under greenhouse conditions

Optimization of the quality and quantity of medicinal materials during cultivation could improve the value of medicinal plants. Light intensity and water availability affect physiological processes and growth of plants. Tulbaghia violacea L. (Alliaceae) bulbs and leaves are widely used traditionally in southern Africa for treatments of many ailments. The interactive effects of light intensity and watering regime on plant growth, nutrient uptake and antifungal activity of T. violacea were evaluated in the current study. Seedlings of T. violacea were grown hydroponically under two shading levels (0% and 40%) while being exposed simultaneously to one of three watering intervals: 5-day, 14-day and 21-day. Different growth parameters (plant height, plant fresh and dry weights) and tissue nutrient contents were evaluated at the end of the experiment. The antifungal activity of acetone extracts on Fusarium oxysporum were evaluated in a microdilution bioassay. Generally, significantly higher concentrations of macronutrients were recorded in the tissue of plants exposed to shorter watering interval. The results showed that different watering frequencies and light intensities significantly (p < 0.05) influenced plant growth parameters (height, and dry and fresh weights). Moreover, there were strong interactive effects of watering frequency and light intensity on most of the plant growth parameters. Remarkably, plants that were simultaneously exposed to the extended watering interval (21-day) and low light intensity showed the best anti-F. oxysporum activity. Key findings of this study revealed that shading alleviated the negative effects of water-deficit stress on plant growth and improved antifungal activity.

Protective role of wild garlic on isoproterenol-induced myocardial necrosis in wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tulbaghia violacea Harv. (TVL) is a folk medicine, native to South Africa which has previously shown antioxidant, anti-hypertensive and anti-diabetic effects.

THE AIM OF THE STUDY

The aim of the current study was to investigate the protective role of wild garlic or TVL on isoproterenol (ISO)-induced myocardial necrosis in rats.

MATERIALS AND METHODS

Animal (n = 6 each group) were pre and co-treated with TVL (60 mg/kg body weight) daily for 30 days. Myocardial necrosis was administrated by subcutaneous injection of ISO (85 mg/kg body weight) into rats on 29th and 30th day. On the 31st day, rats were anaesthetized and blood, heart samples were obtained for the biochemical, histopathological and molecular study. The specific protein target analysis from TVL was done by reverse docking study (reverse pharmacophore mapping) using PharmMapper.

RESULTS

The levels of cardiac markers, lipid peroxidation products, and heart rate were considerably increased in ISO-induced myocardial necrosis in rats whilst plasma enzymatic antioxidants were significantly decreased. Myocardial necrotic mRNA genes were increased in ISO-induced myocardial necrosis in rats compared to controls. Pre and co-treatment with TVL and ramipril of myocardial necrosis in rats showed significant effects on all the biochemical and molecular studies evaluated. TVL reduced heart rate, prevented oxidative stress and downregulated the Fas-receptor and caspase-mediated apoptosis-signaling pathway, and heart muscle damage in myocardial necrosis in rats. The specific target protein [disulfide, bis (2-sulfhydrylethyl] from TVL mediates the protective effects.

CONCLUSION

Wild garlic or TVL extract has shown a protective effect on ISO-induced myocardial necrosis in rats by increasing antioxidant production confirmed with docking studies.

Tulbaghia violacea and Allium ursinum Extracts Exhibit Anti-Parasitic and Antimicrobial Activities

Garlic has played an important role in culinary arts and remedies in the traditional medicine throughout human history. Parasitic infections represent a burden in the society of especially poor countries, causing more than 1 billion infections every year and leading to around one million deaths. In this study, we investigated the mode of anti-parasitic activity of "wild garlics" Tulbaghia violacea and Allium ursinum dichloromethane extracts against parasites Trypanosoma brucei brucei and Leishmania tarentolae with regard to their already known antimicrobial activity. We also evaluated their cytotoxic potential against human cells. Both extracts showed a relevant trypanocidal and leishmanicidal activity, although L. tarentolae was less sensitive. We determined that the probable mode of action of both extracts is the irreversible inhibition of the activity of Trypanosoma brucei trypanothione reductase enzyme. The extracts showed a mild cytotoxic activity against human keratinocytes. They also exhibited weak-in most cases comparable-antibacterial and antifungal activity. HPLC-MS/MS analysis showed that both extracts are abundant in sulfur compounds. Thus, for the first time, the ability of Allium ursinum and Tulbaghia violacea to kill Trypanosoma sp. and Leishmania sp. parasites, probably by binding to and inactivating sulfur-containing compounds essential for the survival of the parasite, is shown.

IN A DIABETIC MODEL

Background:

Diabetes mellitus (DM) is a cluster of metabolic diseases with chronic hyperglycemia as a defining feature, associated with long-term organ damage and dysfunction. In this study we examined the effect of Tulbaghia violacea rhizome methanolic extract on blood glucose and lipids in normal and streptozotocin-induced diabetic rats.

Materials and Methods:

Male Wistar rats (250-300g) were injected intraperitoneally (i.p.) with streptozotocin (60mg/kg body weight) to induce diabetes; or provided with distilled water for the control (CON) (3 ml/kg/b.w.) animals and treatment with TVL (60mg/kg.b.w). The rats were divided into 5 groups of 6 animals per group as follows: Non-diabetic control (NDC)-received distilled water (3ml/kg.b.w), Non-diabetic TVL (ND+TVL)-received TVL (60mh/kg b.w), Diabetic control (DC)-received distilled water (3ml/kg.b.w), Diabetic experimental (D+TVL)-received TVL (60mg/kg.b.w), Diabetic experimental (D+M)-received Metformin (250 mg/kg.b.w). All doses were administered daily via oral gavage.

Results:

TVL-treated animals showed reduced blood glucose, increased plasma insulin, reduced plasma TG, TC, VLDL and increased HDL. Furthermore we found decreased thiobarbituric acid reactive substances (TBARS) and increased superoxide dismutase (SOD) activity and nitric oxide significantly. Regarding renal parameters we found increased blood urea nitrogen (BUN), and improved renal morphology in TVL-treated animals.

Conclusion:

Tulbaghia violacea has a hypoglycaemic effect which could due to its effects on multiple pathways of the hyperglycemic process. Further work is needed to identify the mechanism of its antidiabetic effect.

plant extract affects cell wall synthesis in Aspergillus flavus

AIMS

This study investigates the effect that aqueous extracts of Tulbaghia violacea Harv. harbouring plant saponins, phenolics and tannins have on Aspergillus flavus β-(1,3) glucan and chitin synthesis.

METHODS AND RESULTS

Aspergillus flavus was treated with various subinhibitory concentrations of an aqueous T. violacea plant extract and the β-(1,3) glucan and chitin content was determined together with glucan synthase and chitin synthase production respectively.

CONCLUSIONS

The aqueous extract caused a significant decline (P < 0·05) in β-glucan production in A. flavus in a dose-dependent manner when compared to the untreated sample. Further investigations showed a decrease in β-glucan synthase production as the concentration of the plant extract was increased. A significant reduction in total chitin content corresponding to a decrease in chitin synthase production in the presence of the plant extract was also found.

SIGNIFICANCE AND IMPACT OF THE STUDY

The broad spectrum activity and the efficacy of aqueous T. violacea plant extract on both β-glucan and chitin synthesis may limit the potential of the fungus developing resistance towards it and therefore the extract is an ideal candidate for use as a potential antifungal agent.

In vitro cytotoxic and pro-apoptotic effects of water extracts of Tulbaghia violacea leaves and bulbs

ETHNOPHARMACOLOGICAL RELEVANCE

Infusions of Tulbaghia violacea (wild garlic) in water are used in traditional medicine in Southern Africa to treat numerous diseases, including cancer. Several studies have previously demonstrated the cytotoxic activities of extracts of T. violacea in cultured cancer cells. Their findings support the potential anti-cancer properties of this plant. However, these studies made use of organic solvent extraction methods, while the traditional use of the plant involves the preparation of infusions in water.

MATERIALS AND METHODS

In the current study, we investigated the potential anti-cancer properties of infusions of T. violacea. We also performed a comparative study investigating the cytotoxic activities of T. violacea bulbs and leaves. A panel of four cancer cell lines (HepG2, MCF7, H157, and HT29) and one non-cancerous cell line (KMST6) was treated with the two extracts and the effects of the extracts on the growth of the cells were evaluated. We also investigated whether the growth inhibitory effects were associated with the induction of apoptosis and whether the mechanism of cell death is the result of oxidative stress and the activation of caspase-3.

RESULT

We found that extracts of the leaves and not the bulbs have growth inhibitory effects and that this is the result of the induction of apoptosis, which is associated with the production of Reactive Oxygen Species (ROS) and the activation of caspase-3. The leaf extract demonstrated variable selective toxicity towards the cancer lines. Although the extract also induced cell death in the non-cancerous cell line (KMST6), we found that the levels of toxicity were lower in this cell line.

CONCLUSION

this study confirms that infusions of T. violacea have potential anti-cancer activity and that this bioactivity is contained in the leaf extract. This study lends support to claims that this plant can be used to treat cancer.

(Alliaceae) rhizome methanolic extract on kidney function and morphology in Dahl salt-sensitive rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tulbaghia violacea has been used traditionally for the treatment of several ailments, including hypertension. The herb has been shown to have antihypertensive properties which have been attributed to its angiotensin-converting enzymeinhibitory (ACEI) activity. It could, therefore, prove beneficial in ameliorating renal pathology associated with hypertension. To evaluate the effects of long-term administration of Tulbaghia violacea on renal function and morphology in the Dahl salt-sensitive (DSS) rat model.

MATERIALS AND METHODS

Male DSS rats were treated intra-peritoneally (i.p.) as follows: methanolic extract of Tulbaghia violacea: (TVL) (50 mg/kg/b.w.), captopril: (CAP) (25 mg/kg/b.w.), or distilled water, control: (CON) (3 ml/kg/b.w.). Blood pressure (BP) was measured bi-weekly, whilst 24-h urine volumes and electrolyte concentrations were assessed weekly. Animals were sacrificed on day 49 by halothane overdose. Blood was removed for determination of plasma and serum electrolytes. Left kidney tissues were harvested for the determination of nuclear factor-kappaβ (NF-kβ) and transforming growth factor-β (TGF-β) gene expressions.

RESULTS

TVL significantly reduced mean arterial pressure (MAP) and diastolic blood pressure (DBP). TVL showed reduced blood urea nitrogen, serum creatinine, total protein in urine as well as increased serum total protein. TVL decreased thiobarbituric acid reactive substances (TBARS) and increased glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity and nitric oxide significantly. NF-kβ and TGF-β) gene expressions were significantly reduced in TVL and CAP treated rats. Moreover, renal morphology improved significantly in TVL and CAP treated animals.

CONCLUSION

TVL and CAP demonstrated marked improvement in renal function and morphology.