Acute and Subacute Toxicological Evaluation of the Aerial Extract of Monsonia angustifolia

The acute and subacute toxicity profile of the aerial extract of Monsonia angustifolia in Wistar rats was evaluated. The Organization for Economic Cooperation and Development (OECD) 420 guideline was adopted in the acute toxicity testing with a single oral dose of 5000 mg/kg (b.w.). For the 28-day daily oral dosing, the extract was administered at 75, 150, and 300 mg/kg b.w.; 1% ethanol in sterile distilled water was used as control. Clinical toxicity signs were subsequently evaluated. At a single dose of 5000 mg/kg b.w. the extract elicited no treatment-related signs of toxicity in the animals during the 14 days of experimental period. In the subacute toxicity, there was no significant difference in hematological, renal, and liver function indices. However, dose-dependent significant increases were observed on the plasma concentrations of white blood cell and platelet counts of the treated animals compared to the control group. While cage observations revealed no treatment-facilitated signs of toxicity, histopathological examinations of the kidneys and liver also showed no obvious lesions and morphological changes. These results suggest that the extract may be labelled and classified as safe and practically nontoxic within the doses and period of investigation in this study

Effect of four medicinal plants on amyloid-p induced neurotoxicity in SH-SY5Y cells

Amyloid-beta peptide (Aβ) is implicated in the pathogenesis of Alzheimer’s disease (AD), a neurodegenerative disorder. This study was designed to determine the effect of four medicinal plants used to treat neurodegenerative diseases on Aβ- induced cell death. Cytotoxicity of the ethanol extracts of the plants was determined against SH-SY5Y (human neuroblastoma) cells which were untreated, as well as toxically induced with Aβ, using the MTT and neutral red uptake assays. Cell viability was reduced to 16% when exposed to 20 μM Aβ25-35 for 72 h. The methanol extract of the roots of Ziziphus mucronata Willd., Lannea schweinfurthii (Engl.) Engl. and Terminalia sericea Burch. ex DC., were the least toxic to the SH-SY5Ycells at the highest concentration tested (100 μg/ml). All four plants tested were observed to reduce the effects of Aβ-induced neuronal cell death, indicating that they may contain compounds which may be relevant in the prevention of AD progression.The National Research Foundation (Pretoria) and RESCOM (University of Pretoria).http://journals.sfu.ca/africanem/index.php/ajtcamam2016Pharmacolog

Antioxidant, acetylcholinesterase inhibitory activity and cytotoxicity assessment of the crude extracts of Boophane disticha

1. IntroductionAlzheimer’s disease (AD) is the most commonneurodegenerative disease and is characterized bymemory impairment, cognitive dysfunction, behavioraldisturbances and deficits in daily living (Konrath et al,2012). Approaches to enhance cholinergic function inAD have included stimulation of cholinergic receptorsor prolonging the availability of acetylcholine (ACh)released into the neuronal synaptic cleft by inhibitingACh hydrolysis through the use of acetylcholinesterase(AChE) inhibitors (Howes and Houghton, 2003). Tacrinewas the first widely used AChE inhibitor (Summers,2006). Second generation AChE inhibitors with longerhalf-lives than tacrine, such as donepezil, galanthamineand rivastigmine, have since been developed and arecurrently in use (Shah et al, 2008). In addition, severallines of evidence indicate that reactive oxygen speciesare associated with the pathogenesis of AD, as somecellular characteristics of this disease are either causesor effects of oxidative stress (Zhu et al, 2004; Sultana etal, 2006; Konrath et al, 2012). Generally, thephysiological role of antioxidant compounds is toattenuate the oxidation chain reactions by removingfree-radical intermediates (Liu and Nair, 2010). Since alarge amount of evidence demonstrates that oxidativestress is intimately involved in age-relatedneurodegenerative diseases, there have been a numberof studies which have examined the positive effects ofantioxidants in reducing or blocking neuronal deathoccurring in the pathophysiology of these disorders(Ramassamy, 2006). Consequently, the use ofantioxidants has been explored in an attempt to slowAD progression and neuronal degeneration (Howes andHoughton, 2003).Toxicity testing is an essential requirement for thedevelopment of modern pharmaceutical compounds.Medicinal plants are assumed to have low toxicity dueto their long-term consumption by humans and animals(Luseba et al, 2007; Verschaeve and van Staden, 2008;Aremu et al, 2011). However, several studies haveshown that many plants used as food or medicine, havepotential toxic effects (Du Plooy et al, 2001; Barlow andSchlatter, 2010). Almost all known AChE inhibitors haveseveral drawbacks, such as hepatotoxicity, shortduration of biological action, low bioavailability,adverse cholinergic side effects in the periphery andnarrow therapeutic windows (Lee et al, 2011). Somecommon synthetic antioxidants including butylatedhydroxyanisole (BHA) and butylated hydroxytoluene(BHT) have been reported to be toxic (Aremu et al,2011). Therefore, the search for new AChE inhibitorsand antioxidants, particularly from natural products,with low toxicity and higher efficacy continues.Many plants are reputed to have ‘anti-ageing’ or‘memory-enhancing’ effects and are used traditionallyto treat several neurodegenerative diseases (Howes andHoughton, 2003). One such plant, Boophane disticha(L.f.) Herb. belongs to the family Amaryllidaceae. It is anattractive, deciduous bulbous plant with a thickcovering of dry scales above the ground and is widelydistributed in Africa, ranging from Sudan in the north tothe Western Cape Province in the south (Wrinkle,1984). Decoctions of bulb scales are given to sedateviolent, psychotic patients while bulb infusions arereported to be used to treat mental illness (van Wykand Gericke, 2000; Sobiecki, 2002). Bulb decoctions arealso used in the treatment of headaches, abdominalpain, weakness, sharp chest pains and persistentbladder pains, as well as treatment of varicose ulcers,relief of urticaria, and cancer (Botha et al, 2005). Thisstudy was aimed at evaluating the AChE inhibitory andantioxidant activity of the bulbs and roots of B. distichato partially justify its traditional use in treatment ofneurodegenerative diseases. The safety of using thisplant in traditional medicine was also investigated byassessing its toxicity using the MTT and neutral redassays

Isolation of cycloeucalenol from Boophone disticha and evaluation of its cytotoxicity

Boophone disticha (Amaryllidaceae) is widely used in traditional medicine in southern Africa. Several alkaloids, volatile oils and fatty acids have been isolated from the plant. However, there has been no literature report of a triterpene from B. disticha. Cycloeucalenol, a cycloartane triterpene, together with its regio-isomer, was isolated from the ethyl acetate extract of the bulbs using column chromatography and preparative thin layer chromatography. Structural elucidation was carried out using 1D and 2D NMR and mass spectroscopy. The MTT and neutral red assays were used to assess the cytotoxicity of the compound in human neuroblastoma (SH-SY5Y) cells. The compound was obtained as a mixture of two regio-isomers, which were separated for the first time by chromatographic optimization. Integration of the 1H NMR spectrum showed that cycloeucalenol and its regio-isomer were present in a ratio of 1.04:1. A dose-dependent decrease in cell viability was observed using both cytotoxicity assays. IC51 values of 173.0 +/- 5.1 microM and 223.0 +/- 6.4 microM were obtained for the MTT and neutral red assays, respectively, indicative of the low toxicity of the compound. This work describes for the first time, the presence of triterpene compounds from the genus Boophone.http://www.naturalproduct.us/hb201

In vitro determination of the anti-aging potential of four southern African medicinal plants

BACKGROUND: Aging is an inevitable process for all living organisms. During this process reactive oxygen species generation is increased which leads to the activation of hyaluronidase, collagenase and elastase, which can further contribute to skin aging. Four southern African medicinal plants; Clerodendrum glabrum, Schotia brachypetala, Psychotria capensis and Peltophorum africanum, were investigated to assess their anti-aging properties. METHODS: Anti-elastase, anti-collagenase and anti-hyaluronidase activities of twenty-eight samples, consisting of methanol and ethyl acetate extracts of the four plants, were determined using spectrophotometric methods. Radical scavenging activity was determined by the ability of the plant extracts to scavenge the ABTS•+ radical. RESULTS: The majority of the samples in the anti-elastase assay and nine in the anti-collagenase assay showed more than 80% inhibition. The ethyl acetate extract of S. brachypetala bark and leaves of P. capensis inhibited elastase activity by more than 90%. The methanol extract of S. brachypetala bark contained the highest anti-hyaluronidase activity (75.13 ± 7.49%) whilst the ethyl acetate extract of P. africanum bark exhibited the highest antioxidant activity (IC50: 1.99 ± 0.23 μg/ml). CONCLUSION: The free radical scavenging activity and enzyme inhibitory activity of the plant extracts investigated suggests that they can help restore skin elasticity and thereby slow the wrinkling process. P. africanum was the plant with the most promising activity and will be subjected to further testing and isolation of the active compound/s.The Department of Science and Technology (South Africa), The Council for Scientific and Industrial Research, the University of Pretoria and The European Union (AgroCos FP7 project).http://www.biomedcentral.com/1472-6882/13/304am201

Bioassay guided fractionation of Senna singueana and its potential for development of poultry phytogenic feed additives

There has been burgeoning interest in plant-based feed additives following restrictions placed on the use of antibiotic feed additives in many countries. Phytogenic feed additives are recommended to have a range of useful properties to support the growth and development of poultry to a similar level as that obtained by supplementing feed with antibiotics. The aim of this study was to evaluate the antibacterial, anti-lipoxygenase and antioxidant activity, and in vitro safety of fractions and isolated compounds from leaves of Senna singueana. Antibacterial activities of the fractions and isolated compounds were determined against a panel of bacteria using a two-fold serial microdilution assay and qualitative bioautography assays. Anti-lipoxygenase activity was evaluated using the ferrous oxidation-xylenol orange (FOX) method. Antioxidant activity was assessed qualitatively and quantitatively using radical scavenging assays. Dichloromethane and ethyl acetate fractions from solvent-solvent partitioning had the best antibacterial activity with MIC values ranging from 156 to 313µg/ml. Fractions obtained from column chromatography had significant to weak antibacterial activity with MIC values ranging from 50 to 1,250µg/ml. Bioautography showed clear bands of bacterial inhibition, indicating the presence of a number of active compounds in several fractions. The ethyl acetate fraction and all the tested column fractions had potent anti-lipoxygenase activity with IC50 values of ≤2.5µg/ml which were lower than that of quercetin (positive control), indicating anti-inflammatory potential. The ethyl acetate fraction and several column fractions had powerful antioxidant activity with IC50 values of ≤5µg/ml in the ABTS assay. Cytotoxicity values against Vero kidney cells ranged from LC50 = 40.0–989.3µg/ml. Bioassay-guided fractionation led to the isolation and identification of a known bioactive compound, luteolin. S. singueana is a promising candidate for the development of poultry phytogenic feed additives.The National Research Foundation (NRF) of South Africa and TWAS.https://www.frontiersin.org/journals/veterinary-sciencedm2022Paraclinical Science

Phytochemical isolation of compounds from <i>Sceletium tortuosum</i> and activity testing against <i>Plasmodium falciparum</i>

Malaria is a major health care problem in tropical regions due to the increasing resistance of Plasmodium falciparum against widely available antimalarial drugs. Traditional societies relied on medicinal plants to treat parasitic infections. As a result, drugs like quinine and artemisinin were isolated from herbs and barks (Varughese et al. 2010). Sceletium tortuosum has been used as medicine for social and spiritual purposes by San hunter gatherers and Khoi pastoralists. Sceletium tortuosum is rich in alkaloids, one of the important classes of natural product producing treatment for parasitic infections (Kayser et al. 2002). Laboratory preparation of extracts of fresh S. tortuosum plant material was conducted mimicking traditional methods of preparation using organic solvents. Mesembrine was isolated from a methanol extract using conventional column chromatography. Sixteen extracts and mesembrine were evaluated for antiplasmodium activity using a plasmodium lactate dehydrogenase culture sensitivity assay with chloroquine as reference drug. Of the sixteen extracts, four showed activity against P. falciparum with IC50 ranging between 1.47 µg/mL and 7.32 µg/mL. Extracts prepared from stored material at -20 °C showed no antiplasmodium activity. The four originally active extracts were re-screened six months later, but the antimalarial activity could not be reproduced. To determine discrepancy in biological results, chemical profiling of the extracts was done using high performance liquid chromatography technique. Differences were observed in the profiles of the active extracts when compared to those of stored plant material. The instability of plant constituents observed could be a result of plant storage suggesting that the plant is best used when fresh

Isolation and antioxidant activity of 5-methyldihydroflavasperone from ethanol leaf extract of Guiera senegalensis JF Gmel

BACKGROUND: Guiera senegalensis (Ghibaish) is a medicinal plant extensively used in central and west Africa for the management of various diseases. AIM: This study aimed to determine the antioxidant activity of the ethanol leaf extract of the plant. METHOD: The ethanol leaf extract was sequentially sub-fractionated using liquid–liquid extraction, vacuum-liquid chromatography and preparative thin layer chromatography. Ultraperformance liquid chromatography with accurate mass spectrometry and nuclear magnetic resonance were employed to isolate and confirm the identity of the most abundant compound. The antioxidant activity of the fractions and isolated compound was assessed by bioautography analysis and the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical scavenging assay. RESULTS: The dichloromethane subfraction contained the most promising antioxidant activity (IC50 = 3.18 µg/mL). Purification of this subfraction led to the isolation of a brown crystalline compound, which was identified as 5-methyldihydroflavasperone (IC50 > 4000 µg/mL). CONCLUSION: This is the first report of the isolation of 5-methyldihydroflavasperone from the ethanol leaf extracts of G. senegalensis. This compound was not found to be responsible for the antioxidant activity observed. Further research is warranted to identify the compound responsible for the antioxidant activity.The Sudan Ministry of Higher Education in the form of a scholarship to undertake this study.https://jomped.org/index.php/jompedChemistryPharmacolog

Review on the use of Kojic acid : a skin-lightening ingredient

This article reviews the use of Kojic Acid (KA) as a skin-lightening ingredient in the cosmetics industry. In 1907, Saito discovered KA, a natural product; it has since become one of the most investigated skin-lightening agents. This paper highlights the findings of the research conducted on this agent. It has been found that KA has certain disadvantages, and researchers have attempted to mitigate these disadvantages by designing new equivalents of KA that are more efficient in tyrosinase inhibition. These equivalents are also safe to use and have improved properties and solubility. The Cosmeceutical Ingredient Review (CIR) indicates that this ingredient can be safely used at a concentration not higher than 1% due to its cytotoxicity. Other scientific data also support its safety at a concentration of 2% or less. It was shown to be helpful in the treatment of hyper pigmentary disorders, such as freckles, age spots, post-inflammatory hyperpigmentation, and melasma, which has been proven clinically.The CSIR, Young Researchers Fund, and the APC was funded by the CSIR and The University of Kwa-Zulu Natal, South Africa.https://www.mdpi.com/journal/cosmeticsam2023Chemistr

Cycloartanol and Sutherlandioside C peracetate from Sutherlandia frutescens and their immune potentiating effects

A novel cycloartanol (1) and an acylated Sutherlandioside D (2) together with two known cycloartane derivatives, Sutherlandioside B (3) and Sutherlandioside A (4), were isolated from the aerial parts of Sutherlandia frutescens. The structures of these compounds were established by a combination of 1- and 2-D NMR techniques and further confirmed by high resolution ToF mass spectrometry (HRToFMS). Preliminary biological studies were also conducted to assess the activity of different plant extracts, fractions and compounds on cytokine expression. Compounds 1 and 2 prompted an increase in IL-6 expression while compound 4 showed a reduced IL-6 expression compared to the controls. Compound 1 is an effective suppressor of IL-10 expression. The plant compounds inhibited the expression of the two cytokines, IL-10 and TNFα. The results of the assays suggested that some components in the plant extract influence the immune system by suppressing the expression of IL-6, IL-10 and TNFα.The Council for Scientific and Industrial Research and the University of South Africa.http://www.tandfonline.com/loi/gnpl202020-08-08Chemistr