Urban and agricultural influences on the coastal dissolved organic matter pool in the Algoa Bay estuaries.

While anthropogenic pollution is a major threat to aquatic ecosystem health, our knowledge of the presence of xenobiotics in coastal Dissolved Organic Matter (DOM) is still relatively poor. This is especially true for water bodies in the Global South with limited information gained mostly from targeted studies that rely on comparison with authentic standards. In recent years, non-targeted tandem mass spectrometry has emerged as a powerful tool to collectively detect and identify pollutants and biogenic DOM components in the environment, but this approach has yet to be widely utilized for monitoring ecologically important aquatic systems. In this study we compared the DOM composition of Algoa Bay, Eastern Cape, South Africa, and its two estuaries. The Swartkops Estuary is highly urbanized and severely impacted by anthropogenic pollution, while the Sundays Estuary is impacted by commercial agriculture in its catchment. We employed solid-phase extraction followed by liquid chromatography tandem mass spectrometry to annotate more than 200 pharmaceuticals, pesticides, urban xenobiotics, and natural products based on spectral matching. The identification with authentic standards confirmed the presence of methamphetamine, carbamazepine, sulfamethoxazole, N-acetylsulfamethoxazole, imazapyr, caffeine and hexa(methoxymethyl)melamine, and allowed semi-quantitative estimations for annotated xenobiotics. The Swartkops Estuary DOM composition was strongly impacted by features annotated as urban pollutants including pharmaceuticals such as melamines and antiretrovirals. By contrast, the Sundays Estuary exhibited significant enrichment of molecules annotated as agrochemicals widely used in the citrus farming industry, with predicted concentrations for some of them exceeding predicted no-effect concentrations. This study provides new insight into anthropogenic impact on the Algoa Bay system and demonstrates the utility of non-targeted tandem mass spectrometry as a sensitive tool for assessing the health of ecologically important coastal ecosystems and will serve as a valuable foundation for strategizing long-term monitoring efforts.

Anti-breast cancer potential of Anonidium mannii (Oliv.) Engl. & Diels barks ethanolic extract: UPLC-ESI-QTOF-MS detection of anticancer alkaloids.

ETHNOPHARMACOLOGICAL RELEVANCE: Breast cancer is a serious threat in low-income as well as developed countries. To face this, many herbal preparations are prescribed by traditional healers in Cameroon, among which is Anonidium mannii commonly called "wild soursop". AIM: This study was undertaken to assess the anti-tumor effect of A. mannii ethanolic extract on cancer cell growth and against DMBA-induced mammary tumors in rats. MATERIALS AND METHODS: The well characterized MTT bioassay was used to assess the cytotoxic potential of A. mannii ethanolic extract in liver (HepG2), prostate (DU145 & PC3) and breast (MCF-7) cancer cell lines. Considering the fact that breast cells were the most sensitive to the extract, a 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast tumor rat model was used to assess the possible anticancer effect of A. mannii extract. Indeed, rats were treated with either tamoxifen (3.3 mg/kg BW) or A. mannii extract (16.5, 50 and 150 mg/kg BW) or vehicle (2% ethanol) for 20 weeks. Tumor incidence, tumor mass and volume, oxidative stress status in tumor as well as tumor histoarchitecture were evaluated. RESULTS: A 24 h incubation of tested cells with the A. mannii extract significantly slowed cell growth in a concentration-dependent manner with an interesting effect in breast cells (IC50 ~61.5 µg/mL). As compared to the DMBA rats, those treated with A. mannii extract (50 and 150 mg/kg) showed reduced breast tumor incidence (28%), tumor burden (95.34% at 50 mg/kg and 99.14% at 150 mg/kg) and tumor volume (~92%). A. mannii extract counteracted the high proliferation of terminal mammary ducts induced by DMBA, mainly at 50 mg/kg. Furthermore, the extract decreased MDA and nitrite levels but increased SOD activity in the mammary gland. High Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-MS) analysis detected potential anticancer and antioxidant alkaloids in A. manni extract, which are close to those found in Annona muricata. CONCLUSION: These results provide evidence on the in vitro and in vivo anticancer effects of A. mannii, and therefore support its use in traditional medicine system to fight against cancer.

Co-Loading of Isoniazid-Grafted Phthalocyanine-in-Cyclodextrin and Rifampicin in Crude Soybean Lecithin Liposomes: Formulation, Spectroscopic and Biological Characterization.

An inclusion complex of isoniazid-grafted phthalocyanine with gamma-cyclodextrin (Complex) was co-encapsulated with rifampicin (RIF) in crude soybean lecithin liposomes using a heating method. The encapsulation efficiency (%EE) of the Complex-RIF co-loaded liposomes (Rif-Complex-Lips) was determined using UV-Vis spectrophotometry. Rif-Complex-Lips formulations were evaluated using dynamic light scattering, transmission electron microscopy (TEM), 1H-NMR, absorption and emission spectroscopy. Dialysis was used for drug release study in two different media, pH 6.4 and 7.4. HeLa cells were used to assess potential cytotoxicity, and the uptake by lung fibroblasts and epithelial cells was investigated using fluorescence microscopy. The particle size and Zeta potential of Rif-Complex-Lips were approximately 594 nm and -50 mV. Spectroscopic analyses demonstrated molecular distribution of the cargo within the lipid core, and encapsulation efficiency of 58% for Complex and 86% for RIF. TEM analysis unveiled the existence of spherical nanoparticles in our samples, indicating the presence of liposomes. Rif-Complex-Lips exhibited much higher release rates for both INH and RIF at pH 6.4 compared to those tested at pH 7.4. In addition, there was no cytotoxicity on HeLa cells, but remarkable Rif-Complex-Lips internalization by peripheral lung fibroblasts and epithelial cells. Hence, Rif-Complex-Lips are promising vehicles for intracellular delivery of antimicrobial drugs.

Molecular Networking Reveals Two Distinct Chemotypes in Pyrroloiminoquinone-Producing Tsitsikamma favus Sponges.

The temperate marine sponge, Tsitsikamma favus, produces pyrroloiminoquinone alkaloids with potential as anticancer drug leads. We profiled the secondary metabolite reservoir of T. favus sponges using HR-ESI-LC-MS/MS-based molecular networking analysis followed by preparative purification efforts to map the diversity of new and known pyrroloiminoquinones and related compounds in extracts of seven specimens. Molecular taxonomic identification confirmed all sponges as T. favus and five specimens (chemotype I) were found to produce mainly discorhabdins and tsitsikammamines. Remarkably, however, two specimens (chemotype II) exhibited distinct morphological and chemical characteristics: the absence of discorhabdins, only trace levels of tsitsikammamines and, instead, an abundance of unbranched and halogenated makaluvamines. Targeted chromatographic isolation provided the new makaluvamine Q, the known makaluvamines A and I, tsitsikammamine B, 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C, and the related pyrrolo-ortho-quinones makaluvamine O and makaluvone. Purified compounds displayed different activity profiles in assays for topoisomerase I inhibition, DNA intercalation and antimetabolic activity against human cell lines. This is the first report of makaluvamines from a Tsitsikamma sponge species, and the first description of distinct chemotypes within a species of the Latrunculiidae family. This study sheds new light on the putative pyrroloiminoquinone biosynthetic pathway of latrunculid sponges.

Antiplasmodial Activity of the n-Hexane Extract from Pleurotus ostreatus (Jacq. ex. Fr) P. Kumm.

OBJECTIVES: Several mushrooms species have been reported to be nematophagous and antiprotozoan. This study reported the antiplasmodial and cytotoxic properties of the n-hexane extract from the edible mushroom Pleurotus ostreatus and the isolation of a sterol from the extract. MATERIALS AND METHODS: Antiplasmodial and cytotoxicity assays were done in vitro using the plasmodium lactate dehydrogenase assay and human HeLa cervical cell lines, respectively. The structure of the isolated compound from the n-hexane extract was elucidated using spectroscopic techniques. RESULTS: The n-hexane extract (yield: 0.93% w/w) showed dose dependent antiplasmodial activity with the trend in parasite inhibition of: chloroquine (IC50=0.016 µg/mL) > n-hexane extract (IC50=25.18 µg/mL). It also showed mild cytotoxicity (IC50>100 µg/mL; selectivity index >4) compared to the reference drug emetine (IC50=0.013 µg/mL). The known sterol, ergostan-5,7,22-trien-3-ol, was isolated and characterized from the extract. CONCLUSION: This study reporting for the first time the antiplasmodial activity of P. ostreatus revealed its nutraceutical potential in the management of malaria.

Preparation and characterization of isoniazid-loaded crude soybean lecithin liposomes.

Tuberculosis (TB) is a poverty related infectious disease that is rapidly giving rise to public health concerns. Lengthy drug administration and frequent adverse side-effects associated with TB treatment make anti-tubercular drugs (ATDs) good candidates for drug delivery studies. This work aimed to formulate and prepare liposomes as a cost-effective option for ATD delivery. Liposomes were prepared by film hydration using crude soybean lecithin (CL) and not pure phospholipids as in the normal practice. Cholesterol was also used (up to 25% mass ratio), and isoniazid (INH) was encapsulated as model drug using a freeze-thaw loading technique. Purified soybean lecithin (PL) was also used for comparative purposes, under the same conditions. INH-loaded liposomes were characterized for particle size, Zeta Potential (ZP), encapsulation efficiency (EE) and drug release. Physicochemical properties were investigated using thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared. INH-loaded CL-based liposomes showed high EE (79±2.45%). The average particle size (813.00±9.21nm) and ZP (-42.80±4.31mV) of this formulation are promising for the treatment of TB by pulmonary delivery. These findings suggest the possibility of encapsulating ATDs in liposomes made of crude soybean lecithin that is cheap and readily available.

Anti-malarial synergy of secondary metabolites from Morinda lucida Benth.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots, stem and leaves of Morinda lucida are used in some African countries as treatment against different types of fevers including yellow fever, malaria, trypanosomiasis and feverish conditions during child birth. AIM OF THE STUDY: To determine the in vitro cell toxicity and anti-malarial activity of the extracts of stem bark of M. lucida and to identify the secondary metabolites in the extract that may be responsible for this activity. MATERIALS AND METHODS: The cell toxicity studies of crude extract [dichloromethane (DCM): Methanol (MeOH) in a ratio of1:1 (v/v)] as well as compounds isolated from the same extract were carried out using human cervix adenocarcinoma cells (HeLa cells); while the anti-malarial activities of the same samples were performed against Plasmodium falciparum strain 3D7 using the parasite lactate dehydrogenase (pLDH) assay. The isolation of the active compounds was carried out using chromatographic techniques (column and thin layer chromatography) where as mass spectrometry (MS), Fourier transform infrared spectroscopy (FTIR) as well as 1D- and 2D- nuclear magnetic resonance (NMR) analyses were employed in the characterisation and identification of the isolated secondary metabolites. RESULTS: The pLDH and cell toxicity assays for the crude extract and the fractions of M. lucida indicated that some fractions reduced the malaria parasite viability by approximately 50% at 100µg/mL and they were not significantly cytotoxic. An IC50 done on the crude extract gave a value of 25µg/mL. The % cell viability for the crude extract in cell toxicity assay remained at 100%. Seven chemical constituents i.e. asperuloside (1), asperulosidic acid (2), stigmasterol (3a), ß-sitosterol (3b), cycloartenol (3c), campesterol (3d) and 5,15-O-dimethylmorindol (4) were isolated from the DCM-MeOH extract of stem bark. The isolated compounds tested were not that active by themselves individually at 20µM but their activities were increased when the isolated compounds were combined. As seen when compounds 2, 3 and 4 (% viability: 93, 123 and 101 respectively) were combined yielding an IC50 value of 17µM. Furthermore, this is the first report of compounds 1, 2, 3c, 3d and 4 isolated from M. lucida. CONCLUSION: The crude extract completely suppressed the growth of P. falciparum. This indicates that the crude extract contains many compounds that might be acting in synergy. The observed activity of the crude extract and the samples containing a mixture of different compounds support the traditional use of M. lucida for the treatment of malaria.

Do microplastic loads reflect the population demographics along the southern African coastline?

Plastic pollution is a major anthropogenic contaminant effecting the marine environment and is often associated with high human population densities and industrial activities. The microplastic (63 to 5000µm) burden of beach sediment and surf-zone water was investigated at selected sites along the entire length of the South African coastline. It was predicted that samples collected in areas of high population density, would contain a higher microplastic burden than those along coasts that demonstrate very low population densities. With the exception of water column microplastics within Richard's Bay Harbour (413.3±77.53particles·m-3) and Durban Harbour (1200±133.2particles·m-3), there were no significant spatial differences in microplastic loads. This supports the theory that harbours act as a source of microplastics for the surrounding marine environment. Additionally, the absence of any spatial variation highlights the possible long range distribution of microplastic pollutants by large scale ocean currents.