The diterpene Manool extracted from Salvia tingitana lowers free radical production in retinal rod outer segments by inhibiting the extramitochondrial F1 Fo ATP synthase

Composition and bioactivity of propolis derived from New Zealand native forest

New Zealand's unique indigenous flora has evolved due to its geographical isolation in the Southern Hemisphere. In the 250 years, since European colonisation commenced, much indigenous flora has been replaced by plants largely of Northern Hemisphere origin including poplar species and pine. There are however still a few large areas of principally native flora. The honeybee (Apis mellifera) was introduced to New Zealand in 1839, so has no evolutionary link to the New Zealand indigenous flora. New Zealand propolis from areas in which honeybees have access to poplar and other Northern Hemisphere species is similar in chemical profile to Northern Hemisphere propolis. However, when honeybees were placed in an extensive area of native flora, Te Urewera in the North Island,the chemical profile of propolis produced was vastly different. This "endemic" propolis was characterised by the presence of diterpenoids in contrast to the flavonoids found in poplar-type propolis. These diterpenoids, isocupressic acid, acetyl isocupressic acid, manool, torulosal, communic acid and ferruginol, were characterised by GC-MS and by NMR spectroscopy of the isolated compounds. The "endemic" propolis has commonality with propolis of the Mediterranean-type as well as some Brazilian propolis. Investigation of the bioactivity of a sample of the "endemic" propolis revealed good antioxidant behaviour with a TEAC of 1481 mgtrolox g-1, dose-dependent inhibition of mitochondrial dehydrogenase activity, inhibition of superoxide production with an IC50 of 262 μg mL-1 and inhibition of methicillin resistant and methicillin sensitive S. aureus. Much of this bioactivity can be attributed to the presence of the diterpenoids.

Anticancer diterpenes of African natural products: Mechanistic pathways and preclinical developments

BACKGROUND

The African continent is home to five biodiversity hotspots, boasting an immense wealth of medicinal flora, fungi and marine life. Diterpenes extracted from such natural products have compelling cytotoxic activities that warrant further exploration for the drug market, particularly in cancer therapy, where mortality rates remain elevated worldwide.

PURPOSE

To demonstrate the potential of African natural products on the global stage for cancer therapy development and provide an in-depth analysis of the current literature on the activity of cancer cytotoxic diterpenes from African natural sources (to our knowledge, the first of its kind); not only to reveal the most promising candidates for clinical development, but to demonstrate the importance of preserving the threatened ecosystems of Africa.

METHODS

A comprehensive search by means of the PRISMA strategy was conducted using electronic databases, namely Web of Science, PubMed, Google Scholar and ScienceDirect. The search terms employed were 'diterpene & mechanism & cancer' and 'diterpene & clinical & cancer'. The selection process involved assessing titles in English, Portuguese and Spanish, adhering to predefined eligibility criteria. The timeframe for inclusion spanned from 2010 to 2023, resulting in 218 relevant papers. Chemical structures were visualized using ChemDraw 21.0, PubChem was utilized to search for CID numbers.

RESULTS

Despite being one of the richest biodiverse zones in the world, African natural products are proportionally underreported compared to Asian countries or otherwise. The diterpenes andrographolide (Andrographis paniculata), forskolin (Coleus forskohlii), ent-kauranes from Isodon spp., euphosorophane A (Euphorbia sororia), cafestol & kahweol (Coffea spp.), macrocylic jolkinol D derivatives (Euphorbia piscatoria) and cyathane erinacine A (Hericium erinaceus) illustrated the most encouraging data for further cancer therapy exploration and development.

CONCLUSIONS

Diterpenes from African natural products have the potential to be economically significant active pharmaceutical and medicinal ingredients, specifically focussed on anticancer therapeutics.

Cistus albidus L.-Review of a Traditional Mediterranean Medicinal Plant with Pharmacological Potential

Cistus albidus L. (Cistaceae) is a medicinal plant that has been used therapeutically since ancient times in the Mediterranean basin for its important pharmacological properties. The ability of C. albidus to produce large quantities of a wide range of natural metabolites makes it an attractive source of raw material. The main constituents with bioactive functions that exert pharmacological effects are terpenes and polyphenols, with more than 200 identified compounds. The purpose of this review is to offer a detailed account of the botanical, ethnological, phytochemical, and pharmacological characteristics of C. albidus with the aim of encouraging additional pharmaceutical investigations into the potential therapeutic benefits of this medicinal plant. This review was carried out using organized searches of the available literature up to July 2023. A detailed analysis of C. albidus confirms its traditional use as a medicinal plant. The outcome of several studies suggests a deeper involvement of certain polyphenols and terpenes in multiple mechanisms such as inflammation and pain, with a potential application focus on neurodegenerative diseases and disorders. Other diseases such as prostate cancer and leukemia have already been researched with promising results for this plant, for which no intoxication has been reported in humans.

The Metabolomic Profile of the Essential Oil from Zanthoxylum caribaeum (syn. chiloperone) Growing in Guadeloupe FWI using GC × GC-TOFMS

The essential oil (EO) from the leaves of Zanthoxylum caribaeum (syn. Chiloperone) (Rutaceae) was studied previously for its acaricidal, antimicrobial, antioxidant, and insecticidal properties. In prior studies, the most abundant compound class found in leaf oils from Brazil, Costa Rica, and Paraguay was terpenoids. Herein, essential oil from the leaves of Zanthoxylum caribaeum (prickly yellow, bois chandelle blanc (FWI), peñas Blancas (Costa Rica), and tembetary hu (Paraguay)) growing in Guadeloupe was analyzed with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS), and thirty molecules were identified. A comparison with previously published leaf EO compositions of the same species growing in Brazil, Costa Rica, and Paraguay revealed a number of molecules in common such as β-myrcene, limonene, β-caryophyllene, α-humulene, and spathulenol. Some molecules identified in Zanthoxylum caribaeum from Guadeloupe showed some antimetabolic effects on enzymes; the in-depth study of this plant and its essential oil with regard to metabolic diseases merits further exploration.

The Flavone Cirsiliol from Salvia x jamensis Binds the F1 Moiety of ATP Synthase, Modulating Free Radical Production

Several studies have shown that mammalian retinal rod outer segments (OS) are peculiar structures devoid of mitochondria, characterized by ectopic expression of the molecular machinery for oxidative phosphorylation. Such ectopic aerobic metabolism would provide the chemical energy for the phototransduction taking place in the OS. Natural polyphenols include a large variety of molecules having pleiotropic effects, ranging from anti-inflammatory to antioxidant and others. Our goal in the present study was to investigate the potential of the flavonoid cirsiliol, a trihydroxy-6,7-dimethoxyflavone extracted from Salvia x jamensis, in modulating reactive oxygen species production by the ectopic oxidative phosphorylation taking place in the OS. Our molecular docking analysis identified cirsiliol binding sites inside the F1 moiety of the nanomotor F₁F_o-ATP synthase. The experimental approach was based on luminometry, spectrophotometry and cytofluorimetry to evaluate ATP synthesis, respiratory chain complex activity and H₂O₂ production, respectively. The results showed significant dose-dependent inhibition of ATP production by cirsiliol. Moreover, cirsiliol was effective in reducing the free radical production by the OS exposed to ambient light. We report a considerable protective effect of cirsiliol on the structural stability of rod OS, suggesting it may be considered a promising compound against oxidative stress.

Antihyperglycemic, Antihyperlipidemic, and Antioxidant Effects of Salvia tingitana in Streptozotocin-Induced Diabetic Rats

AIMS

The study aimed to assess the antidiabetic effect of Salvia tingitana (S. tingitana).

BACKGROUND

S. tingitana is an aromatic plant that belongs to the Lamiaceae family. Phytochemical analysis of the aerial parts of S. tingitana revealed the existence of terpenoids and flavonoids. In addition, S. tingitana possesses antimicrobial activity.

OBJECTIVE

The goal of the study was to obtain information about the antihyperglycemic, antihyperlipidemic, antioxidant abilities of S. tingitana aqueous extract.

METHODS

The effect of an acute and sub-chronic administration of S. tingitana aqueous extract (AEST) at the doses of 60 and 80 mg/kg on glucose, lipid profile, and lipoprotein profile was examined in normoglycemic and hyperglycemic rats. Additionally, a preliminary phytochemical screening and the antioxidant activity using DPPH assay were carried out.

RESULTS

Rats treated with AEST at a dose of 60 mg/kg showed a significant decrease in the serum glucose levels during the single oral administration at the 4th and 6th hour of treatment in both normal and streptozotocin(STZ)-induced hyperglycemic rats. Interestingly, a dose of 80 mg/kg AEST produced a significant lowering effect on blood glucose levels at the 2nd, 4th, and 6th hour of treatment after a single oral administration in both diabetic and normal rats. Both doses of AEST (60 and 80 mg/kg) revealed a significant amelioration of lipid and lipoprotein profile. In addition, the qualitative and quantitative phytochemical analysis proved the presence of polyphenols compounds, flavonoids, and tannins. Results suggest that S. tingitana contains some secondary metabolites like alkaloids, phenols, flavonoids, and saponins. Importantly, the study revealed that the aqueous extract of S. tingitana has a very interesting antioxidant activity (IC50 = 553.21 μg/ml).

CONCLUSION

The study illustrates the beneficial action of the aqueous extract of S. tingitana as an antihyperglycemic and antihyperlipidemic agent.