Phytol is a novel tumor promoter on ICR mouse skin

Anti-inflammatory and anxiolytic activities of Euphorbia hirta extract in neonatal asthmatic rats

The current study evaluated the anti-inflammatory and anxiolytic activities of Euphorbia hirta extract in neonatal asthmatic rats. Rats were assigned to the following groups: group I, sham (normal rats); group II, control (asthmatic rats); group III, E. hirta extract (100 µg/100 µl) and group IV, E. hirta extract (200 µg/100 µl). We performed a phytoscreening analysis of E. hirta extract. Inflammatory cell counts in the bronchoalveolar lavage fluid, levels of anti-inflammatory and antioxidant markers, apoptosis, and a histopathological analysis were carried out. An open field test determined anxiolytic activity, an elevated plus maze, a hole board test, and a cross test. The presence of 9,12,15-octadecatrien-1-ol, pentadecylic acid, ethyl linoleate, 1,2,3-trihydroxy benzene, gamma-tocopherol, 5-hydroxymethyl-2-furancarboxaldehyde, myristic acid, 7,10-octadecadienoic acid methyl ester, phytol, ethyl palmitate, and squalene in E. hirta extract was noted. Following treatment with E. hirta extract, total leukocytes, eosinophils, tumor necrosis factor-α (TNF-α), interleukin (IL-6), and lipid peroxidation were reduced, whereas antioxidant levels were increased. The mRNA expression levels of TNF-α, inducible nitric oxide synthase, IL-6, cyclooxygenase-2, caspase-3, p53, nerve growth factor precursor, and Bax were reduced, whereas that of Bcl-2 was increased. Apoptosis and caspase-3 protein expression were significantly reduced. Treatment of rats with E. hirta extract significantly reduced inflammation and eosinophil infiltration in the lungs. Taken together, these results led us to conclude that E. hirta extract has anti-inflammatory and anxiolytic effects on neonatal asthmatic rats with inflammation.

Evaluation of the antioxidant, anti-inflammatory, and anticancer activities of Euphorbia hirta ethanolic extract

This study evaluated the chemical composition, antioxidant, anti-inflammatory and anticancer activities of a Euphorbia hirta L. extract. The antioxidant activities of whole E. hirta ethanol extract were determined by electron spin resonance spectrophotometric analysis of 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydroxyl, and alkyl radical levels and by using an online high-performance liquid chromatography (HPLC)-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay. The E. hirta ethanol extract (0.5 mg/mL) exhibited DPPH-scavenging activity of 61.19% ± 0.22%, while the positive control (0.5 mg/mL ascorbic acid) had 100% ± 0.22% activity. The concentration of the extract required to trap 50% of DPPH (IC₅₀) was 0.205 mg/mL. Online HPLC analysis of the extract also showed strong antioxidant activity. The anti-inflammatory activity of the E. hirta extract was assessed in lipopolysaccharide-induced RAW 264.7 macrophages. The anti-inflammatory activity was highest in the presence of 200 µg/mL E. hirta extract, and nitric oxide production was decreased significantly (p < 0.05). The extract also showed selective anticancer activity at a concentration of 100 µg/mL (p < 0.05). These results indicated that E. hirta may warrant further investigation for the development of antioxidant, anti-inflammatory, and anticancer herbal medications.

Efficacy of phytol-derived diterpenoid immunoadjuvants over alum in shaping the murine host's immune response to Staphylococcus aureus

The ubiquitous gram-positive bacterium Staphylococcus aureus occupies a unique niche in humans for its ability to survive both as a commensal and a life-threatening pathogen. Its complex relationship with the host and its ability to engender a throng of virulence factors, have hindered the development of a successful vaccine against it. The use of immunoadjuvants to enhance host immunity and prevent the shift from commensalism to pathogenicity is a rational approach for containing infection. The objective of this study was to understand the mechanisms by which alum and two phytol-derived immunoadjuvants, phytanol (PHIS-01)(1) and phytanyl chloride (PCl)(2) shape the interaction between S. aureus and its murine host. We studied the effects of the phytol derivatives, relative to alum, on the induction of inflammatory cytokines and chemokines, recruitment of CD11b(+) cells, generation of specific anti-S. aureus antibodies and in vitro clearance of S. aureus. Our results showed that both PHIS-01 and PCl were stronger inducers of protective cytokines IL-17 and IL-1β than alum, and far exceeded alum in enhancing anti-S. aureus antibody response. However, both alum and the phytol derivatives (particularly PCl) promoted efficient recruitment of CD11b(+) cells. Furthermore, PHIS-01, alum and to a lesser extent, PCl were able to up-regulate the expression of key inflammation-related genes that were highly down-regulated by S. aureus alone. In vitro killing assays showed that both PHIS-01 and PCl were far more potent than alum in promoting S. aureus clearance; this indicated their efficiency in shaping an effective anti-S. aureus immune microenvironment. In summary, our study provides evidence for the better effectiveness of phytol-derived immunoadjuvants over alum in enhancing anti-S. aureus immunity.

Synthetic adjuvants for vaccine formulations: phytol derivatives

INTRODUCTION

The development of vaccines is considered a key milestone in preventive medicine. There is no comparable cost-effective means for controlling or eradicating infectious diseases. Yet, a persistent societal problem is the concern about vaccine's safety and long-term effects, and this caters to detractors of vaccination. Pathogen-derived antigen(s) as well as adjuvants/immunostimulants are essential for vaccine efficacy. Currently, adjuvant selection is largely empirical, but the mechanism underlying adjuvanticity is beginning to unravel. This should help develop more defined or targeted adjuvants.

AREAS COVERED

This review provides a brief account and analysis of the host immune parameters modulated by some commonly used as well as new adjuvants, including phytol-based diterpenoids. The major efforts are directed toward evaluating their relative safety and immunomodulatory efficiency, compared to known synthetic and natural adjuvants. Concerns for adverse pathological inflammation and autoimmunity are also addressed.

EXPERT OPINION

The phytol-based adjuvants hold great promise for improving vaccine efficacy, as they cause little or no persistent inflammation, but are highly effective in stimulating a multifaceted immune response, characterized by proficient recruitment of immune cells, generation of antibody and immunological memory, and activation of both Th1 and Th2 responses. Future focus will be on developing cocktail adjuvants to activate the complement system, mobilize follicular T helper cells as well as NKT and γδ T cells and activate cross-presenting dendritic cells to stimulate CD8(+) effector T cells.

Phytol-derived novel isoprenoid immunostimulants

This review describes the adjuvanticity of novel diterpenoids (synthetic phytol derivatives) compared to some commercially available adjuvants. The efficacy of the phytol-derived immunostimulants was evaluated in terms of their ability to activate innate immunity, amplify various antigen-specific immune responses, and engender immunological memory with no discernible adverse effects in both competent and immune-deficient mice. The profile that emerges out of these studies reveals that the phytol derivatives are excellent immunostimulants, superior to a number of commercial adjuvants in terms of long-term memory induction and activation of both innate and acquired immunity. Additionally, the phytol-derived compounds have no cumulative inflammatory or toxic effects even in immuno-compromised mice.

Immune enhancement by novel vaccine adjuvants in autoimmune-prone NZB/W F1 mice: relative efficacy and safety

Background

Vaccines have profoundly impacted global health although concerns persist about their potential role in autoimmune or other adverse reactions. To address these concerns, vaccine components like immunogens and adjuvants require critical evaluation not only in healthy subjects but also in those genetically averse to vaccine constituents. Evaluation in autoimmune-prone animal models of adjuvants is therefore important in vaccine development. The objective here was to assess the effectiveness of experimental adjuvants: two phytol-derived immunostimulants PHIS-01 (phytanol) and PHIS-03 (phytanyl mannose), and a new commercial adjuvant from porcine small intestinal submucosa (SIS-H), relative to a standard adjuvant alum. Phytol derivatives are hydrophobic, oil-in water diterpenoids, while alum is hydrophilic, and SIS is essentially a biodegradable and collagenous protein cocktail derived from extracellular matrices.

Results

We studied phthalate -specific and cross-reactive anti-DNA antibody responses, and parameters associated with the onset of autoimmune disorders. We determined antibody isotype and cytokine/chemokine milieu induced by the above experimental adjuvants relative to alum. Our results indicated that the phytol-derived adjuvant PHIS-01 exceeded alum in enhancing anti-phthalate antibody without much cross reactivity with ds-DNA. Relatively, SIS and PHIS-03 proved less robust, but they were also less inflammatory. Interestingly, these adjuvants facilitated isotype switching of anti-hapten, but not of anti-DNA response. The current study reaffirms our earlier reports on adjuvanticity of phytol compounds and SIS-H in non autoimmune-prone BALB/c and C57BL/6 mice. These adjuvants are as effective as alum also in autoimmune-prone NZB/WF1 mice, and they have little deleterious effects.

Conclusion

Although all adjuvants tested impacted cytokine/chemokine milieu in favor of Th1/Th2 balance, the phytol compounds fared better in reducing the onset of autoimmune syndromes. However, SIS is least inflammatory among the adjuvants evaluated.

Immunohistochemical study of inducible nitric oxide synthase in skin cancers

BACKGROUND

Nitric oxide (NO) is synthesized from the amino acid L-arginine by NO synthase (NOS). Experimental evidence suggests that increased express of inducible NOS (iNOS), which is an NOS isoform and calcium independent, is related to various pathological processes, such as inflammation and cancer.

METHODS

In this study, we used immunohistochemistry to investigate iNOS expression in a series of basal cell carcinomas (BCC), Bowen's disease, squamous cell carcinomas (SCC), extramammary Paget's disease (EPD) and metastatic tumors of the skin.

RESULTS

Only 1 of 16 BCC cases was positive for iNOS and the intensity of staining was weak. In most of the 10 cases of Bowen's disease, iNOS was weakly expressed and there was a wide range in the percentage of positive tumor cells. Twelve of the 16 cases of SCC were positive for iNOS and the extent of positivity was greater than in Bowen's disease. Two of the 7 cases of EPD were positive for iNOS, and 12 of the 15 cases of metastatic cancer were positive. Well-differentiated adenocarcinomas were diffusely positive, whereas poorly-differentiated ones showed strong and heterogeneous staining.

CONCLUSIONS

These results indicated that the expression of iNOS may reflect the proliferation of tumor cells and that a heterogeneous distribution of iNOS may correlate with a wide variety of biological behavior of tumor cells.