Pittosporum viridiflorum Sims (Pittosporaceae): A review on a useful medicinal plant native to South Africa and tropical Africa

Structure, anti-inflammatory and anti-bacterial activities of novel pentacyclic triterpenoids and other constituents from the leaves of Pittosporum elevaticostatum

The investigation of the leaves of Pittosporum elevaticostatum Chang et Yan led to the isolation of fifteen pentacyclic triterpenoids (1-15), including five previously undescribed ones (1-5), and nine others (16-24). The structures of compounds 1-5 were elucidated based on comprehensive spectroscopic techniques, including one dimension (1D) and 2D nuclear magnetic resonance (NMR), high resolution electrospray ionization mass spectroscopy (HR-ESI-MS), and other methods. Compounds 2 and 13 demonstrated significant inhibitory activity against Listeria monocytogenes (L. monocytogenes) with minimum inhibitory concentration (MIC) values of 32 μM. Scanning electron microscopy (SEM) observations revealed insights into the antibacterial mechanism, indicating that compounds 2 and 13 either prevent biofilm formation of dispersed the preformed cell membranes. Additionally, compounds 1, 5, 7, and 12 exhibited anti-inflammatory activity on lipopolysaccharide (LPS)-stimulated BV-2 microglial cells with IC50 values ranging from 11.27 to 17.80 μM.

Comparative and phylogenetic analysis of the complete chloroplast genomes of ten Pittosporum species from East Asia

Pittosporum (Pittosporaceae) is famous as the ornamental and medical values, which is distributed tropical and subtropical regions of Eastern Hemisphere. The few phylogenetic studies have included samples from the Pacific Island, but the phylogenetic relationships of Asian species has not been studied. Here, the complete chloroplast (cp) genomes of ten Pittosporum species from East Asia were first sequenced and compared with those of the published species of this genus. Our results indicated that cp genomes of these species had a typical and conserved quadripartite structure. 131 genes were identical in order and orientation and no changes of inverted repeat (IR) occurred. However, the comparative analysis of cp genomes suggested that sequence divergence mainly appeared in non-coding or intergenic regions, in which several divergence hotspots were identified. By contrast, protein-coding genes showed the lowest variance under strong purifying selection. Phylogenetic analysis based on the cp genome sequences showed that the tested Pittosporum species were clustered into two major clades, in which the Asian species formed Clade I and the remaining species from Australia and New Zealand formed Clade II with high support values, which was consistent with the results of ITS data with low support values. These results suggested that cp genome is a robust phylogenetic indicator for deep nodes in the phylogeny of Pittosporum. Meanwhile, these results will provide the valuable information to better understand the phylogeny and biogeography of Pittosporum.

Eudesmane sesquiterpenoid glycosides from the leaves of Pittosporum lenticellatum with anti-neuroinflammatory activity

Chemical investigation of the EtOAc extract of the leaves of Pittosporum lenticellatum led to the isolation of twenty-five previously undescribed eudesmane sesquiterpenoid glycosides, pitlencosides A－Y (1-25); their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR, HR-ESI-MS, ECD spectra, and X-ray crystallographic analysis. Among them, compounds 4, 5, 7, 8, 15 and 16 exhibited significant inhibitory effects on the production of nitric oxide in lipopolysaccharide-induced BV-2 microglial cells by suppressing the expression of inducible nitric oxide synthase and cyclooxygenase-2, with IC50 values ranging from 7.95 to 25.88 μM, which showed stereo-chemical and substituent dependents. Western blot analysis and molecular docking simulation confirmed the anti-inflammatory activity of compounds 4, 5, 7, 8, 15 and 16.

Further sesquiterpenoids from Pittosporum qinlingense and their anti-inflammatory activity

Four new sesquiterpenoid glycoside esters, Pitqinlingoside N-Q (1-4), together with eleven known metabolites (5-15), were isolated from 95% EtOH extract of the twigs, fruits and leaves of P. qinlingense. The structures of new compounds were elucidated on the basis of extensive spectroscopic analyses, including IR, UV, HRMS, NMR and electronic circular dichroism spectra. Unusal glycoside esters are characterized by the presence of polyacylated β-D-fucopyranosyl and β-d-glucopyranosyl units. Pitqinlingoside N (1), O (2), P (3), boscialin (5) and arvoside C (6) showed significant nitric oxide production inhibition in lipopolysaccharide (LPS)-induced BV-2 microglial cells with IC₅₀ values ranging from 1.58 to 28.74 μM. Structure-activity relationships of the isolated compounds are discussed.

The Tip of the Iceberg: Cryopreservation Needs for Meeting the Challenge of Exceptional Plant Conservation

Cryopreservation is increasingly important as a conservation tool, particularly for threatened exceptional species. The goal of this study was to investigate the current knowledge of plant cryopreservation through a search of the literature in Web of Science and align that with the 775 species currently identified on the Working List of Exceptional Plants. While there is a good foundation in plant cryopreservation research, particularly with economically important species, there are significant gaps in research on families that contain the largest numbers of currently known exceptional species, including the Dipterocarpaceae, Rhizophoraceae, and Pittosporaceae. Even families well represented in both in the literature and on the List of Exceptional Plants had much less overlap at the level of genus. Tropical trees, a significant portion of exceptional species, were not as well represented in the literature as herbaceous species. Over 70% of all articles dealt with in vitro cryopreservation, with much less emphasis on other methods (seed, embryo, dormant bud, and pollen) that will be more cost-effective for species where they can be applied. While the research on plant cryopreservation to date provides a strong foundation and is being utilized effectively for conserving the diversity of a number of economically important species, this study revealed significant gaps that can help prioritize future research to more effectively conserve the diversity of threatened exceptional species.

Structurally Diverse Sesquiterpenoid Glycoside Esters from Pittosporum qinlingense with Anti-neuroinflammatory Activity

Thirteen new sesquiterpenoid glycoside esters, including 11 aromadendrane-type compounds, pitqinlingosides A-K (1-11), one cadinane-type compound, pitqinlingoside L (12), and one eudesmane-type compound, pitqinlingoside M (13), together with seven known analogues (14-20) were isolated from the twigs, fruits, and leaves of Pittosporum qinlingense. Structures were elucidated by analysis of spectroscopic data, gas chromatography mass spectrometry (GC-MS), and chemical methods. The absolute configuration was confirmed by single-crystal X-ray crystallography analysis or electronic circular dichroism spectra. Unusual glycoside esters are characterized by the presence of polyacylated β-d-fucopyranosyl, β-d-glucopyranosyl, and β-d-xylopyranosyl units. Pitqinlingosides A (1), B (2), D (4), and F (6), pittosporanoside A₁ acetate (14), and pittosporanoside A₁ (16) showed significant nitric oxide production inhibition in lipopolysaccharide (LPS)-induced BV-2 microglial cells with IC₅₀ values ranging from 0.95 to 24.12 μM. Structure-activity relationships of the isolated compounds are discussed.

Plants Used for the Traditional Management of Cancer in the Eastern Cape Province of South Africa: A Review of Ethnobotanical Surveys, Ethnopharmacological Studies and Active Phytochemicals

Cancer occurrence is rapidly increasing all over the world, including in developing countries. The current trend in cancer management requires the use of herbal remedies since the majority of anticancer drugs are known to be costly, with unwanted side effects. In the Eastern Cape province, the use of medicinal plants for cancer management has been climbing steadily over the past two decades due to their cultural belief, low cost, efficacy, and safety claims. With the aim of identifying some potential anticancer plants for probable drug development, this study was undertaken to review plants reported by ethnobotanical surveys in the Eastern Cape province of South Africa for the traditional management of cancer. Information regarding plants used for cancer management in the Eastern Cape province was obtained from multidisciplinary databases and ethnobotanical books. About 24 plant species belonging to twenty families have been reported to be used for the traditional management of cancer in the Eastern Cape province. Among the anticancer plant species, only 16 species have been explored scientifically for their anticancer activities. This review authenticated the use of anticancer plant species in the Eastern Cape province and, therefore, identified several promising unexplored species for further scientific evaluation.

South Africa's Best BARK Medicines Prescribed at the Johannesburg Muthi Markets for Skin, Gut, and Lung Infections: MIC's and Brine Shrimp Lethality

Indigenous trade of medicinal plants in South Africa is a multi-million-rand industry and is still highly relevant in terms of primary health care. The purpose of this study was to identify today's most traded medicinal barks, traditionally and contemporaneously used for dermatological, gastrointestinal, and respiratory tract infections; then, to investigate the antimicrobial activity and toxicity of the respective extracts and interpret outcomes in light of pharmacokinetics. Thirty-one popularly traded medicinal barks were purchased from the Faraday and Kwa Mai-Mai markets in Johannesburg, South Africa. Information on the medicinal uses of bark-based medicines in modern commerce was recorded from randomly selected traders. The minimum inhibitory concentration (MIC) method was used for antimicrobial screening, and brine shrimp lethality was used to determine toxicity. New medicinal uses were recorded for 14 bark species. Plants demonstrating some broad-spectrum activities against tested bacteria include Elaeodendron transvaalense, Erythrina lysistemon, Garcinia livingstonei, Pterocelastrus rostratus, Rapanea melanophloeos, Schotia brachypetala, Sclerocarya birrea, and Ziziphus mucronata. The lowest MIC value of 0.004 mg/mL was observed against Staphylococcus epidermidis for a dichloromethane bark extract of E. lysistemon. The tested medicinal barks were shown to be non-toxic against the Artemia nauplii (brine shrimp) bioassay, except for a methanol extract from Trichilia emetica (69.52% mortality). Bacterial inhibition of bark extracts with minimal associated toxicity is consistent with the safety and valuable use of medicinal barks for local muthi market customers. Antimicrobial outcomes against skin and gastrointestinal pathogens are feasible because mere contact-inhibition is required in vivo; however, MIC values against respiratory pathogens require further explaining from a pharmacokinetics or pharmacodynamics perspective, particularly for ingested rather than smoked therapies.

Nutritional Value and Antimicrobial Activity of Pittosporum angustifolium (Gumby Gumby), an Australian Indigenous Plant

The indigenous endemic plant P. angustifolium has received attention for nutraceutical and therapeutic applications in Australia. This study investigates for the first time the nutritional value (macro- and micronutrients, minerals, trace elements, polyphenols, carotenoids, saponins and antioxidant capacity) and antimicrobial activity of different botanical parts of P. angustifolium, either collected from the wild or cultivated. Different botanical tissues, geographic location and growing condition (wild vs. cultivated) showed significant (p < 0.05) effects on the tested bioactive compounds, with the leaves having significantly (p < 0.05) higher levels than the stems. Saponins and polyphenols could be identified as the main bioactive compounds in the leaves with up to 4% per dry weight. The extracts of P. angustifolium leaves and stems showed strong antioxidant and antimicrobial activities, especially against Candida albicans. These activities correlated (R2 = 0.64-0.92; p < 0.05) with the levels of polyphenols and saponins, indicating their biologic potential. Findings from this study may provide information for future applications of P. angustifolium in the functional ingredient or nutraceutical industry.

Scientific rationale for traditional use of plants to treat tuberculosis in the eastern region of the OR Tambo district, South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Tuberculosis (TB) remains a major health problem for humans worldwide, and was responsible for 1.4 million human deaths in 2015 alone. Although there is treatment for TB, emerging multi-drug, extensively drug and totally drug resistant forms of this disease, as well as co-infection with human immunodefiency virus (HIV) continue to worsen the situation. South Africa is among countries with reported traditional use and published documentation of such knowledge concerning the use of plants against TB. Based on a previous study where plants used traditionally for treating TB in the eastern region of OR Tambo district, South Africa, were documented, the present study aimed to determine the antimycobacterial effect, cytotoxicity and genotoxicity of plants selected from that list.

MATERIAL AND METHODS

Acetone, 70% ethanol, cold and hot water extracts were tested for antimycobacterial activity against saprophytic Mycobacterium species including M. aurum, M. bovis BCG, M. gordonae, M. fortuitum, and M. smegmatis using a microdilution method. Extracts with MIC values less than 1 mg/ml against at least three Mycobacterium strains were evaluated for antimycobacterial activity against pathogenic Mycobacterium strains including M. tuberculosis H37RV, M. tuberculosis and M. bovis, cytotoxicity (against Vero monkey kidney and bovine dermis cells), and genotoxicity (against Salmonella typhimurium TA98 and TA100).

RESULTS

The MIC values of the extracts ranged from 0.02 to 2.50 mg/ml, LC₅₀ values of twenty-nine extracts ranged from 0.001 to > 1 mg/ml and the highest selectivity index was 79.50, an extremely promising value. Phymaspermum acerosum roots and leaves (ethanol and water) extracts had the best MIC value (0.02 mg/ml) against at least one Mycobacterium strain. It was interesting to note the lack of cytotoxicity of these extracts with the highest selectivity index value of 39.75. Pterocelastrus echinatus bark acetone and Protorhus longifolia leaf hot water extracts were the most cytotoxic with LC₅₀ = 0.001 and 0.008 mg/ml, respectively, whereas Pittosporum viridiflorum bark water extract was genotoxic. Among non-pathogenic strains, M. gordonae, M. aurum, M. smegmatis showed good correlation of activity with pathogenic M. tuberculosis H37Rv, M. tuberculosis and M. bovis, however, M. aurum was the best predictor with Mycobacterium tuberculosis H37Rv (correlation coefficient value = 0.73).

CONCLUSION

The results indicate that Heteromorpha trifoliata and Phymaspermum acerosum should be investigated further for antimycobacterial efficacy against drug resistant strains of Mycobacterium.