An examination of the phenol-croton oil peel: Part I. Dissecting the formula

This article investigates which ingredients are the active ones in the most popular peel formula. The benefits of the "phenol" peel have been attributed to the effects of phenol on the dermis. Baker published a simple peel formula in 1962 that became a classic that has been used since by almost all plastic surgeons and dermatologists. Brown et al., in 1960, passed along a set of dogmas: (1) phenol is the active ingredient; (2) phenol peels more deeply in lower concentrations; and (3) adding a surface tension-lowering agent increases the peel. This article seeks to dissect the Baker formula by removing the croton oil. A patient was peeled serially with 18% phenol, 35% phenol, and 50% phenol solutions containing Septisol (surface tension-lowering agent) but no croton oil. This showed that increasing concentrations of phenol caused more clinical tissue reaction as evidenced by edema and erythema, but no significant dermal injury was seen. USP 88% phenol without Septisol did cause injury to the dermis. To test the effect of croton oil in the formula, the patient's face was peeled with two variations: the perioral area was peeled with 50% phenol to which croton oil was added to a strength of 2.1% and the remainder with 50% phenol without croton oil. The perioral area showed vesiculation, slough, and dermal exposure characteristic of a deep peel requiring 11 days to heal. The remainder of the face treated with 50% phenol without croton oil showed only edema and erythema without significant dermal injury. This experiment shows that the main postulates of Brown et al.--that phenol in lesser concentrations peels more than in higher concentrations and that phenol is the sole agent--are not true. In a fourth peel, a 0.7% concentration of croton oil in 50% phenol was applied to the parts of the face not peeled with croton oil in the third peel. The areas peeled with 50% phenol with 0.7% croton oil healed in 7 days, whereas the treatment with 50% phenol with 2.1% croton oil required 11 days. Deconstructing the Baker formula reveals fallacies in the four-decade-long belief system regarding these peels. The serial peels performed in this study show that increasing concentrations of phenol without croton oil cause increasing skin reaction but insignificant peeling effect. The addition of croton oil to 50% phenol, however, causes a marked increase in the depth of peeling into the dermis. Lowering the concentration of croton oil caused a lesser burn, as evidenced by fewer days to heal. The depth of the peel, therefore, seems to be more dependent on the concentration of croton oil than phenol. This will be further explored in Parts II, III, and IV.     

An examination of the phenol-croton oil peel: Part III. The plastic surgeons' role

In Part II, the author focused on the lay peelers' history and success using croton oil-containing phenol peeling recipes. In Part III, the author reviews what was known or should have been known about croton oil and phenol as physicians became keenly interested in face peeling in the mid-1950s. The lay peelers recognized that croton oil was a critical ingredient of the so-called phenol peel while physicians focused on phenol without recognizing the intense cytotoxic effect of croton resin. Physicians have persisted in this systematic error for 40 years. Both dermatology and plastic surgery have shown a remarkable credulity about phenol's action and lack of curiosity about croton oil's action. A hitherto unreferenced and unknown croton oil-containing formula of Adolph Brown, patented in 1959, has been unearthed, preceding Litton's and Baker's formulas in time. The recollections of Litton, Baker, Truppman, and Georgiade shed some light on the interaction between them and the lay peelers and how the formulas were transferred. Other plastic surgeons probably acquired the same knowledge, used it in their practices, but chose not to draw attention to it. None of the physicians credited the lay peelers. Brown, Litton, and Baker each could have published a complete formula, but only Baker did. However, his formula was vastly stronger than the lay formulas but, nevertheless, came to dominate medical peeling for the next 35 years because of its simplicity of preparation. A review of the peel literature reveals many oft-repeated but unsupported dogmas regarding the mode of action of phenol, which have obscured our understanding of the phenol-croton oil peel. Animal studies exist that refute these dogmas, e.g., (1) lesser concentrations of phenol wound more deeply; and (2) phenol has an all-or-nothing action. As well, studies from the early 1980s showed that the presence of croton oil caused much deeper burns than phenol alone. Suggested areas of research that could solve the conundrum of the phenol-croton oil peel are presented.     

An examination of the phenol-croton oil peel: Part II. The lay peelers and their croton oil formulas

From the turn of the century, lay face peelers, known as "skinners," ran "beautifier" salons. Beginning in the 1920s, lay peelers were using croton oil-phenol formulas in Hollywood. These persons were renowned, made a good living, and treated many, if not most, of the leading "stars" of the day. They had a treatment, a "secret," that physicians did not. Physicians brought their own wives to the peelers for their expertise. The leading lay peel personalities from the 1920s through to our time are presented. The lay peelers dominated the field until the 1960s, when legal attacks on them, often directly instigated by the newly educated physician peelers, put them at a legal disadvantage. Nevertheless, there was considerable interaction with many plastic surgeons along the way. Some plastic surgeons came into possession of the techniques and some also into knowledge of the ingredients in a formula. The author has presented the recipes of four of the renowned lay peelers, two from Hollywood, Gradé and Kelsen, and two from Miami, Coopersmith and Maschek. These recipes all have 80 to 90 percent less croton oil than the "classic" Baker formula and, therefore, wound less deeply. The Hollywood formulas were used on many celebrities both inside and outside the film world from the 1920s to the early 1990s. These lay recipes are cumbersome to prepare. The author has simplified the preparation of these lay recipes by using USP liquid phenol instead of crystals. These simple formulas are provided in a table and are as easy to prepare as the Baker formula.     

台琼海桐蒴果皮油及籽油的主要挥发性化学成分

采用GC-MS技术,对台琼海桐蒴果皮的水蒸气蒸馏油样,以及蒴果籽的索氏提取油样的甲酯化样品进行分析。样品中各化学成分的相对含量用面积归一化法确定。在实验条件下,果皮油样共分离出24个峰,鉴定了17个,占总峰面积的94.70%。其主要成分为柠檬烯(24.27%)、γ-榄香烯(8.30%)、β-榄香烯(17.13%)、α-榄香烯(16.02%)、长叶龙脑(15.52%)和α-松油醇(2.17%),α-石竹烯(1.88%)。果籽油的甲酯化样品共分离出16个峰,鉴定了12个,占总峰面积的96.69%,其主要成分为棕榈油酸(34.83%)、反油酸(26.63%)、14-甲基-十五烷酸(17.08%),十八烷酸(1.88%),十四烷酸(1.61%)。分析结果说明台琼海桐蒴果皮富含挥发性芳香油,而蒴果籽油含有多种脂肪酸。     

Resistance to pathogens in terpene down-regulated orange fruits inversely correlates with the accumulation of D-limonene in peel oil glands

Volatile organic compounds (VOCs) are secondary metabolites acting as a language for the communication of plants with the environment. In orange fruits, the monoterpene D-limonene accumulates at very high levels in oil glands from the peel. Drastic down-regulation of D-limonene synthase gene expression in the peel of transgenic oranges harboring a D-limonene synthase transgene in antisense (AS) configuration altered the monoterpene profile in oil glands, mainly resulting in reduced accumulation of D-limonene. This led to fruit resistance against Penicillium digitatum (Pd), Xanthomonas citri subsp. citri (Xcc) and other specialized pathogens. Here, we analyze resistance to pathogens in independent AS and empty vector (EV) lines, which have low, medium or high D-limonene concentrations and show that the level of resistance is inversely related to the accumulation of D-limonene in orange peels, thus explaining the need of high D-limonene accumulation in mature oranges in nature for the efficient attraction of specialized microorganism frugivores.     

Adjunctive treatment of congenital pigmented nevi with phenol chemical peel

The purpose of this study was a retrospective evaluation of the treatment of congenital pigmented nevi using the phenol chemical peel technique. Patients were treated with standard Baker formula in the operating room under general anesthesia or intravenous sedation with continuous electrocardiogram monitoring. A total of 20 patients were reviewed (13 girls and 7 boys, mean age 3.8 years). Eight patients had nevi located on the face, five patients had trunk lesions, and three patients had lesions on the thighs. Two patients had nevi located on both the face and the trunk, and two patients had involvement of the face, trunk, and thigh. Three of the above patients had the classic "bathing trunk" distribution of the nevi. A test area was peeled in four patients, and in five patients preoperative biopsies were performed to rule out malignancy before initiation of therapy. An average of 2.6 treatments were performed per patient. Two patients had adjunctive dermabrasion to increase the depth of peel and to contour surface irregularities. The length of follow-up ranged from 6 to 84 months with a mean of 28 months. Healing of the wounds occurred within 2 to 3 weeks postoperatively. Seventy-five percent of patients had satisfactory cosmetic improvement in the appearance of the lesions following treatment. Four patients had recurrence of the pigmentation after an initial lightening response, three of whom had their nevi subsequently excised. There was no incidence of hypertrophic scarring or cardiac and/or renal complications. There was one death from complications of leptomeningeal melanocytosis. Chemical peeling of congenital pigmented nevi is an acceptable alternative method of therapy for those lesions that are too large for excision and primary closure or for lesions in which excision would result in unacceptable scars in areas such as the face.     

Quantitative and qualitative effects of chemical peeling on photo-aged skin: an experimental study

Chemical peel reverses the visible stigmata of photo aging in human skin. The qualitative and, in particular, the quantitative changes in the dermis that effect this transformation are unclear. This study used a recognized photo-aged animal model, the Skh:HR-1 hairless mouse, to quantify and qualify the changes that occurred in collagen and glycosaminoglycan content after chemical peel. One hundred Skh:HR-1 hairless mice were photo-aged by use of chronic ultraviolet B irradiation for 14 weeks. After irradiation the animals were randomly distributed into five groups of 20 mice each: group 1, control; group 2, 50% glycolic acid peel; group 3, 30% trichloroacetic acid peel; group 4, 50% trichloroacetic acid peel; group 5, phenol peel (Baker-Gordon formula). The respective peeling agent was applied to the dorsal skin of each animal while it was fully anesthetized. Punch biopsies were taken at several times after peel for histological and biochemical analysis. Glycosaminoglycan content was assessed at 14, 28, and 60 days using a colorimetric assay. Collagen content per unit volume increased initially 3 days after the procedure in all chemical peel groups, declining on day 7, and peaking again on day 28. Significant elevations (p < 0.04) were seen in the 30% trichloroacetic acid, 50% trichloroacetic acid, and phenol peels on days 3 and 28 in comparison with controls. This increase in collagen content was not maintained and returned to control values by 60 days. Glycosaminoglycan content per unit volume was elevated initially after peel with significant elevation (p < 0.02) in the 50% trichloroacetic acid and phenol groups on days 14 and 28. This increase in glycosaminoglycan content was not maintained beyond 28 days and declined to control values by day 60 in all groups. Histological examination demonstrated an increase in dermal thickness in the 50% trichloroacetic acid and phenol groups in comparison with controls by day 60. Under polarized light all chemical peel groups at day 60 demonstrated a reorganization of collagen in the reticular and papillary dermis. The elastotic masses that are pathognomonic of photo aging were present in the control group but were absent in the peel groups and demonstrated a reorganization of the elastic fibers in the dermis. This effect was deeper in the dermis in the deeper peel groups (50% trichloroacetic acid and phenol peel). The beneficial effects of chemical peel were due to a combination of two findings; a reorganization in dermal structural elements and an increase in dermal volume. These effects were more pronounced in the deeper peel groups.     

Coumarins and psoralens in grapefruit peel oil

Four coumarins, four psoralens and two methoxyflavones were isolated and identified from the peel oil of grapefruit. Five of these compounds are reported as constituents of grapefruit oil for the first time, one of which, 5[(3,7-dimethyl-6-epoxy-2-octenyl) oxy]psoralen is a new natural product.     

Studies on the development of functional powder from citrus peel

The suitability of citrus peels, generated as a by-product of the juice industry, as a source of antioxidants was investigated. Citrus peel powder was prepared by lyophilizing 70% ethanol extract from citrus peels. Extraction was carried out at room temperature (20 degrees C) for 72 h. The extract was subjected to gamma-irradiation treatment (20 kGy). The aqueous solutions of citrus peel powder were examined for color characteristics and antioxidant potential in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, beta-carotene bleaching and nitrite scavenging activities. There were significant changes in Hunter color values due to irradiation. The a*- and b*-values decreased due to radiation treatment. DPPH radical scavenging, beta-carotene bleaching and nitrite scavenging activities were not affected by irradiation treatment. Nitrite scavenging activity was the highest in the extract at pH 1.2 followed by pH 4.2 and 6.0. These functional properties of the aqueous solution were found to be stable in heat treatment. It could significantly improve oxidative stability of lipids in fish meat system. Based on these results there may be opportunities to use citrus peel powder as a functional component in the food processing industry with gamma irradiation treatment improving its color characteristics without adversely influencing the functional properties.     

Evaluation of characteristic aroma compounds of Citrus natsudaidai Hayata (Natsudaidai) cold-pressed peel oil

The characteristic aroma compounds of Citrus natsudaidai Hayata essential oil were evaluated by a combination of instrumental and sensory methods. Sixty compounds were identified and quantified, accounting for 94.08% of the total peel oil constituents. Limonene was the most abundant compound (80.68%), followed by gamma-terpinene (5.30%), myrcene (2.25%) and alpha-pinene (1.30%). Nineteen compounds which could not be identified in the original oil were identified in the oxygenated fraction. Myrcene, linalool, alpha-pinene, beta-pinene, limonene, nonanal, gamma-terpinene, germacrene D, and perillyl alcohol were the active aroma components (FD-factor > 3(6)), whereas beta-copaene, cis-sabinene hydrate and 1-octanol were suggested as characteristic aroma compounds, having a Natsudaidai-like aroma in the GC effluent. Three other compounds, heptyl acetate, (E)-limonene oxide and 2,3-butanediol, which each showed a high RFA value (>35) were considered to be important in the reconstruction of the original Natsudaidai oil from pure odor chemicals. The results indicate that 1-octanol was the aroma impact compound of C. natsudaidai Hayata peel oil.     

Effect of orange peel essential oil on oxidative stress in AOM animals

The processing parameters of pump speed, inlet air temperature, outlet air temperature and homogenization pressure were evaluated. Encapsulation efficiency is high with a satisfied releasing rate. Then, acute otitis media (AOM) animal model was built and diet containing orange peel essential oil microcapsules were administrated to AOM animals. Pharmacological test showed that orange peel essential oil treatment could decrease serum and cochlea malondialdehyde (MDA), immunoglobulins A (IgA), immunoglobulins G (IgG), immunoglobulins M (IgM) levels and increase antioxidant enzymes activities. It can be concluded that orange peel essential oil treatment could decrease oxidative injury in acute otitis media rats.     

Lemon peel and Limoncello liqueur: A proteomic duet

Combinatorial peptide ligand libraries (CPLLs) have been adopted for investigating the proteomes of lemon peels and pulp, of a home-made alcoholic infusion of peels and of a very popular Italian liqueur called “Limoncello”, stated to be an infusion of the flavedo (the outer, yellow skin of lemons). The aim of this study was not only to perform the deepest investigation so far of the lemon peel proteome but also to assess the genuineness of the commercial liqueur via a three-pronged attack. First, different extraction techniques have been used for the characterization of the peel (and additionally of the pulp) proteome, secondly a home-made infusion has been analysed and finally the proteome of the commercial drink was checked. The peel (the flavedo, not the underlying layer called albedo) proteome has been evaluated via prior capture with CPLLs at different pH values (2.2 and 7.2). Via mass spectrometry analysis of the recovered fractions, after elution of the captured populations in 4% boiling SDS, we could identify a total of 1011 unique gene products in the peel extracts and 674 in the pulp, 264 proteins in the home-made infusion and just 8 proteins (and protein fragments), together with 12 peptides, in one Italian Limoncello produced in the Sorrento Region, thus proving the genuineness of this product. On the contrary, cheaper Limoncellos were devoid of any protein/peptide, casting doubts on their production from vegetable extracts. This could be the starting point for investigating the genuineness and natural origin of commercial drinks in order to protect consumers from adulterated products.     

Antidiabetic potential of Citrus sinensis and Punica granatum peel extracts in alloxan treated male mice

An investigation on the effects of four different concentrations of peel extract from Citrus sinensis (CS) or Punica granatum (PG) in male mice revealed the maximum glucose lowering and antiperoxidative activities at 25 mg/kg of CS and 200 mg/kg of PG. In a separate experiment their potential was evaluated with respect to the regulation of alloxan induced diabetes mellitus. While a single dose of alloxan (120 mg/kg) increased the serum levels of glucose and alpha-amylase activity, rate of water consumption and lipid peroxidation (LPO) in hepatic, cardiac and renal tissues with a parallel decrease in serum insulin level, administration of 25 mg/kg of CS or 200 mg/kg of PG was found to normalize all the adverse changes induced by alloxan, revealing the antidiabetic and anti peroxidative potential of test fruit peel extracts. Subsequent phytochemical analysis indicated that the high content of total polyphenols in the test peels might be related to the antidiabetic and antiperoxidative effects of the test peels.     

Supercritical fluid extraction of naringin from the peel of Citrus paradisi

The highest yield (14.4 g/kg) of naringin, the major flavonoid from the peel of Citrus paradisi L., that could be achieved by supercritical fluid extraction was obtained using supercritical carbon dioxide modified with 15% ethanol and fresh (rather than dried) peels at 95 bar and 58.6 degrees C. This yield is higher than that attained by the conventional technique of maceration, and close to those obtained by reflux and Soxhlet methods. Furthermore, supercritical fluid extraction consumes less solvent and provides a shorter extraction time than conventional extraction methods.     

The effect of treatment with urea, sorbic acid, or dehydration on orange peel silage

The purpose of this work was to study the effects of 1% urea, 0.05% sorbic acid (SA) and moderate dehydration (by oven at 35°C for 1 h) on the ensiling process of orange peels and on reducing fermentation losses.

Fresh peels of the various treatments, in 10-kg triplicates, were ensiled in specially designed anaerobic containers for 35 days. Chemical and microbial analyses were performed on the peels and on seepage samples taken during the ensiling period.

The dominant microbial populations of the peel silage were lactobacilli (10⁸ g per DM) and yeasts (10⁵ g per DM) and the major fermentation product was ethanol (16% in DM of the control silage). There were differences between the treatments, with SA being the only treatment effective in reducing DM losses to 15%, compared with > 30% for the other treatments. Chemical results indicate a more efficient fermentation process with SA.     

Laryngeal edema as a complication of chemical peel

Laryngeal edema is a rare complication in patients undergoing chemical face peels. Symptoms of stridor, hoarseness, and tachypnea developed within 24 hours after peeling and subsided within another 24 hours after inhalation therapy with heated aerosol mist was begun. All patients who developed this complication were heavy smokers. A possible mechanism by which this complication was produced is discussed and experience with a drug regimen to prevent its occurrence is presented.     

Cometabolic degradation of 4-chlorophenol by Alcaligenes eutrophus

 Alcaligenes eutrophus was grown in batch cultures using either phenol as a sole substrate or mixtures of phenol and 4-chlorophenol. Phenol was found to be the sole source for carbon and energy while 4-chlorophenol was utilized only as a cometabolite. Maximum growth rates on phenol reached only 0.26 h^-1, significantly below the growth rates reported earlier with Pseudomonas putida. The cometabolite was found to decrease biomass yield and increase lag time before logarithmic growth occurred. Both phenol and 4-chlorophenol were found to inhibit the growth rate linearly with maximum concentrations of 1080 ppm and 69 ppm respectively, beyond which no growth occurred. The best-fit parameters are incorporated into a simple, dynamic (i.e. time-varying) model capable of predicting all the batch growth conditions presented here. It is shown that P. putida is capable of faster bioremediation when phenol is the sole carbon source or for mixed substrates with low concentrations of the cometabolite, but for high concentrations of 4-chlorophenol, A. eutrophus becomes superior because of the long lag times that occur in the Pseudomonas species. Received: 25 January 1996/Received revision: 13 March 1996/Accepted: 15 April 1996     

Effects of high temperature coupled with high light on the balance between photooxidation and photoprotection in the sun-exposed peel of apple

The sun-exposed peel of 'Gala' apple with or without sunburn was compared in terms of photooxidation and photoprotection, and a controlled experiment was conducted to probe the initial responses of PSII to high light and high temperature. The content of carotenoids, lutein and xanthophylls on a chlorophyll basis was higher in the sunburned peel although they were lower expressed on a peel area basis. Significant loss of beta-carotene and neoxanthin was observed relative to chlorophylls in the sunburned peel. O(2) evolution rates and the activity of key enzymes in the Calvin cycle were lower in the sunburned peel, but the activity of these enzymes decreased to a lesser extent than the O(2) evolution rates. The activity of antioxidant enzymes in the ascorbate-glutathione cycle and the level of total ascorbate, total glutathione, and reduced glutathione were higher in the sunburned peel. However, the sunburned peel had higher H(2)O(2) and malondialdehyde contents. Fruit peels treated with high temperature (45 degrees C) alone showed a clear "K" step in their chlorophyll fluorescence transients whereas high temperature coupled with high light (1,600 mumol m(-2) s(-1)) led to the disappearance of the "K" step and a further decrease in F (V)/F (M) (similar to what was observed in the sunburned peel). We conclude that high temperature coupled with high light damages the PSII complexes at both the donor and acceptor sides. Although both the xanthophyll cycle and the antioxidant system are up-regulated in response to the photooxidative stress, this up-regulation does not provide enough protection against the photooxidation.     

Simultaneous saccharification and fermentation of citrus peel waste by Saccharomyces cerevisiae to produce ethanol

The effects of d-limonene concentration, enzyme loading, and pH on ethanol production from simultaneous saccharification and fermentation (SSF) of citrus peel waste by Saccharomyces cerevisiae were studied at 37 °C. Prior to SSF, citrus peel waste underwent a steam explosion process to remove more than 90% of the initial d-limonene present in the peel waste. d-Limonene is known to inhibit yeast growth and experiments were performed where d-limonene was added back to peel to determine threshold inhibition amounts. Ethanol concentrations after 24 h were reduced in fermentations with initial d-limonene concentrations greater than or equal to 0.33% (v/v) and final (24 h) d-limonene concentrations greater than or equal to 0.14% (v/v). Ethanol production was reduced when enzyme loadings were (IU or FPU/g peel dry solids) less than 25, pectinase; 0.02, cellulase; and 13, beta-glucosidase. Ethanol production was greatest when the initial pH of the peel waste was adjusted to 6.0.