Carrier oils in dermatology

Efficacy of Topical Essential Oils in Musculoskeletal Disorders: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Essential oils (EOs) are widely used topically in musculoskeletal disorders (MSDs); however, their clinical efficacy is controversial. Our aim was to find evidence that topical EOs are beneficial as an add-on treatment in MSDs. We performed a systematic review and meta-analysis to summarize the evidence on the available data of randomized controlled trials (RCTs). The protocol of this work was registered on PROSPERO. We used Web of Science, EMBASE, PubMed, Central Cochrane Library and Scopus electronic databases for systematic search. Eight RCTs were included in the quantitative analysis. In conclusion, EO therapy had a favorable effect on pain intensity (primary outcome) compared to placebo. The greatest pain-relieving effect of EO therapy was calculated immediately after the intervention (MD of pain intensity = −0.87; p = 0.014). EO therapy had a slightly better analgesic effect than placebo one week after the intervention (MD of pain intensity = −0.58; p = 0.077) and at the four-week follow-up as well (MD of pain intensity = −0.52; p = 0.049). EO therapy had a beneficial effect on stiffness (a secondary outcome) compared to the no intervention group (MD = −0.77; p = 0.061). This systematic review and meta-analysis showed that topical EOs are beneficial as an add-on treatment in reducing pain and stiffness in the investigated MSDs.

The Antimicrobial and Toxicity Influence of Six Carrier Oils on Essential Oil Compounds

Essential oil compounds have been identified as alternative antimicrobials; however, their use is limited due to their toxicity on human lymphocytes, skin, and reproduction. Carrier oils can reduce the toxicity of essential oils, which raises the question as to whether such activity would extend to the essential oil compounds. Thus, this study aimed to investigate the antimicrobial and toxicity activity of essential oil compounds in combination with carrier oils. The antimicrobial properties of the essential oil compounds, alone and in combination with carrier oils, were determined using the broth microdilution assay. The toxicity was determined using the brine shrimp lethality assay. Antimicrobial synergy (ΣFIC ≤ 0.50) occurred in 3% of the samples when tested against the ESKAPE pathogens. The compound thymoquinone in combination with the carrier oil Prunus armeniaca demonstrated broad-spectrum synergistic activity and a selectivity index above four, highlighting this combination as the most favorable. The carrier oils reduced the toxicity of several compounds, with Calendula officinalis and P. armeniaca carrier oils being responsible for the majority of the reduced toxicity observed. This study provides insight into the interactions that may occur when adding a carrier oil to essential oil compounds.

Effectiveness of aromatherapy for prevention or treatment of disease, medical or preclinical conditions, and injury: protocol for a systematic review and meta-analysis

BACKGROUND

Aromatherapy - the therapeutic use of essential oils from plants (flowers, herbs or trees) to treat ill health and promote physical, emotional and spiritual well-being - is one of the most widely used natural therapies reported by consumers in Western countries. The Australian Government Department of Health (via the National Health and Medical Research Council) has commissioned a suite of independent evidence evaluations to inform the 2019-20 Review of the Australian Government Rebate on Private Health Insurance for Natural Therapies. This protocol is for one of the evaluations: a systematic review that aims to examine the effectiveness of aromatherapy in preventing and/or treating injury, disease, medical conditions or preclinical conditions.

METHODS

Eligibility criteria: randomised trials comparing (1) aromatherapy (delivered by any mode) to no aromatherapy (inactive controls), (2) aromatherapy (delivered by massage) to massage alone or (3) aromatherapy to 'gold standard' treatments.

POPULATIONS

any condition, pre-condition, injury or risk factor (excluding healthy participants without clearly identified risk factors).

OUTCOMES

any for which aromatherapy is indicated. Searches: Cochrane Central Register of Controlled Trials (CENTRAL), with a supplementary search of PubMed (covering a 6-month lag period for processing records in CENTRAL and records not indexed in MEDLINE), AMED and Emcare. No date, language or geographic limitations will be applied.

DATA AND ANALYSIS

screening by two authors, independently (records indexed by Aromatherapy or Oils volatile or aromatherapy in title; all full text) or one author (remaining records) with second author until 80% agreement. Data extraction and risk of bias assessment (ROB 2.0) will be piloted by three authors, then completed by a single author and checked by a second. Comparisons will be based on broad outcome categories (e.g. pain, emotional functioning, sleep disruption) stratified by population subgroups (e.g. chronic pain conditions, cancer, dementia) as defined in the analytic framework for the review. Meta-analysis or other synthesis methods will be used to combine results across studies. GRADE methods will be used to assess certainty of evidence and summarise findings.

DISCUSSION

Results of the systematic review will provide a comprehensive and up-to-date synthesis of evidence about the effectiveness of aromatherapy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021268244.

Comparison of mechanical, chemical and physical human models of in vivo skin damage: Randomized controlled trial

INTRODUCTION

Human in vivo models of skin damage were often used in research of cutaneous disorders. The most commonly used models were tape-stripping as mechanical, sodium lauryl sulphate-induced irritation as chemical and ultraviolet radiation as physical damage model. In regard to differences between models, they were expected to have different responses to damage and recovery, with unique skin parameters' changes over time.

OBJECTIVE

The aim was to compare skin parameters in three different skin damage models on the same anatomical location, with and without topical treatment.

METHODS

Four test sites on each forearm were randomly assigned to three skin damage models with the fourth sites on each forearm chosen as a control, undamaged site. Skin parameters were assessed using non-invasive methods.

RESULTS

Sodium lauryl sulphate irritation caused the strongest damage with delayed reaction to the irritant. Tape stripping leads to highest initial skin barrier disruption but afterwards it showed the fastest skin recovery. Ultraviolet radiation did not affect skin barrier function, but it elevated skin erythema and melanin level. Tested preparation did not lead to changes in measured parameters.

CONCLUSION

The skin of the participants had different response to three skin damage models with distinct changes of skin parameters and recovery. The trial was registered at ClinicalTrials.gov under the identifier NCT03783819.