Evaluation of Lippia scaberrima Sond. and Aspalathus linearis (Burm.f.) R. Dahlgren extracts on human CYP enzymes and gold nanoparticle synthesis: implications for drug metabolism and cytotoxicity

BACKGROUND

Metabolism is an important component of the kinetic characteristics of herbal constituents, and it often determines the internal dose and concentration of these effective constituents at the target site. The metabolic profile of plant extracts and pure compounds need to be determined for any possible herb-drug metabolic interactions that might occur.

METHODS

Various concentrations of the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with fermented and unfermented Aspalathus linearis extract were used to determine the inhibitory potential on placental, microsomal and recombinant human hepatic Cytochrome P450 enzymes. Furthermore, the study investigated the synthesis and characterization of gold nanoparticles from the ethanolic extract of Lippia scaberrima as a lead sample. Confirmation and characterization of the synthesized gold nanoparticles were conducted through various methods. Additionally, the cytotoxic properties of the ethanolic extract of Lippia scaberrima were compared with the gold nanoparticles synthesized from Lippia scaberrima using gum arabic as a capping agent.

RESULTS

All the samples showed varying levels of CYP inhibition. The most potent inhibition took place for CYP2C19 and CYP1B1 with 50% inhibitory concentration (IC50) values of less than 0.05 µg/L for the essential oil tested and IC50-values between 0.05 µg/L-1 µg/L for all the other combinations and extracts tested, respectively. For both CYP1A2 and CYP2D6 the IC50-values for the essential oil, the extracts and combinations were found in the range of 1 - 10 µg/L. The majority of the IC50 values found were higher than 10 µg/L and, therefore, were found to have no inhibition against the CYP enzymes tested.

CONCLUSION

Therefore, the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with Aspalathus linearis do not possess any clinically significant CYP interaction potential and may be further investigated for their adjuvant potential for use in the tuberculosis treatment regimen. Furthermore, it was shown that the cytotoxic potential of the Lippia scaberrima gold nanoparticles was reduced by twofold when compared to the ethanolic extract of Lippia scaberrima.

Assessment of the in Vitro Antimelanoma Potential of Lippia microphylla Cham (Verbenaceae) Essential Oil

Essential oils stand out among natural products for their complex composition, frequently described in the literature with a range of biological effects. This study evaluated the cytotoxic activity against several human cancer cell lines of essential oils extracted from the leaves of Lippia microphylla (EO-LM) Cham. (Verbenaceae). The melanoma cell line SK-MEL-28 was the most sensitive to the EO-LM, presenting an IC50 of 33.38±1.16 μg/mL. Afterward, the effects of EO-LM on the cell cycle, induction of apoptosis, and production of reactive oxygen species (ROS) were evaluated. We stated a significant increase in the sub-G1 population, indicating apoptosis, later confirmed by an increase of SK-MEL-28 cells labeled with Annexin V-FITC and by the formation of apoptotic bodies and membrane blebs, observed by confocal microscopy. Additionally, EO-LM reduced the production of ROS, indicating antioxidant activity. Therefore, EO-LM exhibits anti-melanoma activity in vitro, suggesting its potential as an anticancer agent.

Lippia grata essential oil complexed with β-cyclodextrin ameliorates biochemical and behavioral deficits in an animal model of progressive parkinsonism

Parkinson's disease (PD) is identified by the loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc), and is correlated to aggregates of proteins such as α-synuclein, Lewy's bodies. Although the PD etiology remains poorly understood, evidence suggests a main role of oxidative stress on this process. Lippia grata Schauer, known as "alecrim-do-mato", "alecrim-de-vaqueiro", "alecrim-da-chapada", is a native bush from tropical areas mainly distributed throughout the Central and South America. This plant species is commonly used in traditional medicine for relief of pain and inflammation conditions, and that has proven antioxidant effects. We evaluated the effects of essential oil of the L. grata after its complexed with β-cyclodextrin (LIP) on PD animal model induced by reserpine (RES). Behavioral assessments were performed across the treatment. Upon completion the treatment, the animals were euthanized, afterwards their brains were isolated and processed for immunohistochemical and oxidative stress analysis. The LIP treatment delayed the onset of the behavior of catalepsy, decreased the number of oral movements and prevented the memory impairment on the novel object recognition task. In addition, the treatment with LIP protected against dopaminergic depletion in the SNpc and dorsal striatum (STRd), and decreased the α-syn immunoreactivity in the SNpc and hippocampus (HIP). Moreover, there was reduction of the oxidative stability index. These findings demonstrated that the LIP treatment has neuroprotective effect in a progressive parkinsonism model, suggesting that LIP could be an important source for novel treatment approaches in PD.

Involvement of the PKA pathway and inhibition of voltage gated Ca2+ channels in antihyperalgesic activity of Lippia grata/β-cyclodextrin

Neuropathic pain (NP) is a difficult condition to treat because of the modest efficacy of available drugs. New treatments are required. In the study we aimed to investigate the effects of the essential oil from Lippia grata alone or complexed in β-cyclodextrin (LG or LG-βCD) on persistent inflammatory and neuropathic pain in a mouse model. We also investigated Ca²⁺ currents in rat dorsal root ganglion (DRG) neurons. Male Swiss mice were treated with LG or LG/β-CD (24 mg/kg, i.g.) and their effect was evaluated using an acute inflammatory pleurisy model and nociception triggered by intraplantar injection of an agonist of the TRPs channels. We also tested their effect in chronic pain models: injection of Freund's Complete Adjuvant and partial sciatic nerve ligation (PSNL). In the pleurisy model, LG reduced the number of leukocytes and the levels of TNF-α and IL-1β. It also inhibited cinnamaldehyde and menthol-induced nociceptive behavior. The pain threshold in mechanical and thermal hyperalgesia was increased and paw edema was decreased in models of inflammatory and neuropathic pain. PSNL increased inflammatory protein contents and LG and LG-βCD restored the protein contents of TNF-α, NF-κB, and PKA, but not IL-1β and IL-10. LG inhibited voltage gated Ca²⁺ channels from DRG neurons. Our results suggested that LG or LG-βCD produce anti-hyperalgesic effect in chronic pain models through reductions in TNF-α levels and PKA, and inhibited voltage-gated calcium channels and may be innovative therapeutic agents for the management of NP.

Ecophysiological response of Lippia gracilis (Verbanaceae) to duration of salt stress

The objective of this work was to investigate the effects of salinized water on Lippia gracilis by determining the ion accumulation capacity and morphophysiological changes as a function of salinity and time of exposure to stress. L. gracilis was irrigated with water containing different concentrations of salts and electrical conductivities. The analyses were conducted 25 and 50 days after stress (DAS), in leaf, stem/branches, and roots. Plant height (Hplants), basal stem diameter (Φstem), and mean unitary leaf area (ULA) were determined. After that, the plant material was dried, and the total dry biomass (TDB) (in g plant^-1), leaf dry biomass (LDB), stem dry biomass (SDB), and the roots dry biomass (RDB) were determined. Based on these data, the following variables were calculated: total leaf area (TLA) in cm² plant^-1; biomass allocation fraction (BAF) obtained by dividing the biomass of the stem, leaves, and roots, separately, with the total plant biomass; relative growth rate (RGR); net assimilation rate (NAR); leaf area ratio (LAR); specific leaf area (SLA); and sclerophylly index (SI). The concentrations of potassium and sodium ions were quantified by atomic absorption spectrophotometry and the chloride ion concentration was determined by argentometric titration. L. gracilis showed a variable response to salt stress as a function of time, having a considerable capacity to withstand an increasing load of toxic ions, while maintaining a positive growth rate, highlighting the potential use of the species in moderately saline environments.

Study of the influence of wavelengths and intensities of LEDs on the growth, photosynthetic pigment, and volatile compounds production of Lippia rotundifolia Cham in vitro

Lippia rotundifolia Cham. is in the family Verbenaceae and is endemic to the Cerrado. This species is aromatic and characterized by the presence of glandular trichomes on its leaves that are rich in monoterpenes. The objective of this study was to evaluate the growth, photosynthetic pigment production, and chemical composition of L. rotundifolia grown in vitro under different light wavelengths and intensities. The light intensities consisted of five treatments using cool white fluorescent lamps at 20, 54, 78, 88, and 110 μmol m^-2 s^-1. The light quality consisted of six treatments using light-emitting diodes (LEDs) in different light wavelengths, namely, white, red, blue, and their interactions: 1R:1B, 2.5R:1B, and 1R:2.5B. After 45 days, the biometric parameters, photosynthetic pigment content, and volatile compounds were evaluated. The lower light intensities of 20 and 54 μmol m^-2 s^-1 generated higher growth, photosynthetic pigment content, and biomass accumulation. Myrcene and pentadecane were highest under light intensities of 88 and 110 μmol m^-2 s^-1, respectively. The highest limonene and ocimenone levels were obtained at 20 and 54 μmol m^-2 s^-1 intensity, respectively, and the highest myrcenone content was obtained at 78 μmol m^-2 s^-1 intensity. Regarding the light wavelengths, the combination of red and blue spectra further stimulated plantlet growth, and the 2.5R:1B combination obtained the best biometric data and total chlorophyll content. The z-ocimenone chemical compound contents were highest under the 1R:2.5B light spectrum. The monochromatic blue spectrum increased the myrcene and limonene content but decreased the myrcenone content, which was increased by red light. The highest pentadecane contents were obtained with the white spectrum and the red and blue combinations.

Growth performance, blood parameters, carcass characteristics and meat quality traits in Potchefstroom Koekoek chickens fed Lippia javanica leaf meal

Lippia javanica leaves may have nutraceutical bioactivity and thus could be a viable alternative to antibiotic growth promoters in poultry diets. To test this hypothesis, a feeding trial was carried out to determine the effects of dietary inclusion of Lippia javanica leaf meal (LJ) on growth performance, blood parameters, carcass characteristics and meat quality of indigenous Potchefstroom Koekoek (PK) chickens. The leaf meal was used to dilute a commercial chicken grower diet at a rate of 25 or 50 g/kg diet. Two additional experimental diets, a positive control (commercial chicken grower diet with antibiotics, CON+) and a negative control (commercial chicken grower diet without antibiotics, CON-), were also formulated. Feed intake and growth performance were measured over a period of 13 weeks before slaughtering for carcass and meat quality measurements. Blood was collected in week 11 to determine haematological and serum biochemical parameters. Diet had no effect on overall FCE but significantly (P < 0.05) affected bilirubin, alanine aminotransferase (ALT), aspartate transaminase (AST), sodium, potassium, cholesterol and magnesium levels in blood. When included at 50 g/kg, LJ increased carcass weight (P < 0.05). Meat from CON- (6.07) and LJ50 (6.08) chickens had a higher pH than from CON+ (5.9) and LJ25 (5.8) chickens. Breast muscle in CON- chickens had higher (P < 0.05) lightness (L*) value (53.2) compared to chickens fed on other diets. It was observed that meat from LJ25 chickens had the highest for redness value (2.3). It was concluded that L. javanica leaf meal can be included up to 50 g/kg in Potchefstroom koekoek chicken diets without causing negative effects on the birds' feed intake, utilisation and weight gain. Diet-induced changes observed in blood parameters and meat quality fell within the expected normal ranges for indigenous chickens.

Morphology and histochemistry of the glandular trichomes of Lippia scaberrima (Verbenaceae)

BACKGROUND AND AIMS

Lippia scaberrima, an aromatic indigenous South African plant, with medicinal application, potentially has economic value. The production of essential oil from this plant has not been optimized, and this study of the chemico-morphological characteristics was aimed at determining the location of oil production within the plant. Furthermore, the locality of other secondary metabolites important in medicinal applications needed to be ascertained. This information would be useful in deciding the protocol required for isolation of such compounds.

METHODS

The morphology of the glandular trichomes was investigated using a combination of scanning electron and light microscopy. Concurrently, the chemical content was studied by applying various chemical reagents and fluorescence microscopy.

KEY RESULTS

Three types of trichomes were distinguished on the material investigated. Large, bulbous peltate glands containing compounds of terpenoid nature are probably the main site of essential oil accumulation. Small glands were found to be both peltate and capitate and fluorescent stain indicated the possible presence of phenolic compounds. The third type was a slender tapered seta with an ornamented surface and uniseriate base, and evidently secretory in nature.

CONCLUSIONS

This study linking the chemical content and morphology of the glandular trichomes of L. scaberrima has contributed to the knowledge and understanding of secretory structures of Lippia spp. in general.

Total assignments of 1H and 13C NMR spectra of isocatalpanol and a derivative of tecomaquinone

Isocatalpanol and tecomaquinone I were obtained from roots of Lippia sidoides, a medicinal plant from northeast Brazil. Reduction of tecomaquinone I with NaBH4 yielded a new derivative. Structural elucidation was done on the basis of spectral data, mainly by high-field NMR and electron ionization mass spectrometry.

[Oregano: properties, composition and biological activity]

The oregano spice includes various plant species. The most common are the genus Origanum, native of Europe, and the Lippia, native of Mexico. Among the species of Origanum. their most important components are the limonene, gamma-cariofilene, rho-cymenene, canfor, linalol, alpha-pinene, carvacrol and thymol. In the genus Lippia, the same compounds can be found. The oregano composition depends on the specie, climate, altitude, time of recollection and the stage of growth. Some of the properties of this plant's extracts are being currently studied due to the growing interest for substituting synthetic additives commonly found in foods. Oregano has a good antioxidant capacity and also presents antimicrobial activity against pathogenic microorganisms like Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, among others. These are all characteristics of interest for the food industry because they may enhance the safety and stability of foods. There are also some reports regarding the antimutagenic and anticarcinogenic effect of oregano; representing an alternative for the potential treatment and/or prevention of certain chronic ailments, like cancer.