November 6, 2019

Aloe Polysaccharide and Propolis as Potential Chemopreventive Agents in Smokers

Results of a randomized, multi-arm, blinded, placebo-controlled study
Naturally sourced products helped test subjects eliminate harmful chemicals associated with cigarette smoking and induced changes in blood contents that suggest a protective effect on the kidneys and liver.


Koo HJ, Lee KR, Kim HS, Lee B-M. Detoxification effects of aloe polysaccharide and propolis on the urinary excretion of metabolites in smokers. Food Chem Toxicol. 2019;130:99-108.

Study Objective

To assess the potential application of aloe polysaccharide and propolis as chemoprevention in smokers by measuring the effects of these natural agents on urinary excretion of major tobacco carcinogens and nicotine. To explore the synergistic effects of aloe polysaccharide and propolis by using a combination of these agents at lower doses.


Randomized, multiarm, blinded, placebo-controlled study, 4-week duration

Participants and Intervention

A total of 50 participants divided into 5 groups of 10 each.

Forty healthy smokers (20-40 cig/day x 1-10 y) and 10 healthy non-smokers (never smokers). All males, 20 to 28 years old. All students at Sungkyunkwan University, Suwon, Republic of Korea.

Group 1. 10 non-smokers. Placebo.

Group 2. 10 smokers. Placebo

Group 3. 10 smokers. 600 mg/day of aloe polysaccharide extract

Group 4. 10 smokers. 600 mg/day of propolis extract

Group 5. 10 smokers: mixture of 420 mg/day of aloe polysaccharide and 180 mg/day of propolis

Study Parameters Assessed

  • Urinary excretion of benzo[a]pyrene (BaP) and cotinine
  • Blood levels of creatinine, glucose, and total bilirubin

Primary Outcome Measures

  • Urine levels of BaP and cotinine
  • Blood levels of creatinine, glucose, and total bilirubin

Study Limitations

All participants were young, East-Asian males.

Key Findings

Urinary excretion of BaP and cotinine was significantly increased in a time-dependent manner by treatment with aloe polysaccharide, propolis, and a mixture of the 2 agents. Treatment with aloe polysaccharide alone had a greater impact on the urinary excretion of BaP and cotinine (BaP, 2.23-fold increase; cotinine, 2.64-fold increase versus smoker placebo group) than treatment with propolis (BaP, 1.30-fold increase; cotinine, 2.08-fold increase; P<0.05).

The mixture of aloe polysaccharide and propolis at lower doses had an effect (BaP, 2.33-fold increase; cotinine, 2.28-fold increase vs smoker placebo group) similar to that of aloe polysaccharide alone at a higher dose, demonstrating synergistic effects of aloe and propolis products.

The enhanced excretion of carcinogens may be chemopreventive by limiting the interaction of electrophilic carcinogens with biomolecules.

Blood levels of creatinine, glucose, and total bilirubin were decreased by aloe polysaccharide alone (15.24%, 40.22%, and 48.82%, respectively), propolis alone (16.83%, 36.25%, and 52.59%, respectively), and the mixture of aloe polysaccharide and propolis (16.36%, 46.37%, and 39.20%, respectively; P<0.05).

Practice Implications

Tobacco products cause numerous cancers, as well as cardiovascular, respiratory, and various inflammatory diseases. According to the World Health Organization, about 8 million people die each year worldwide as a result of tobacco use; more than 7 million deaths are the result of direct tobacco use and 1.2 million are due to exposure to second-hand smoke.1 In the United States, cigarette smoking is the leading cause of preventable disease and death. Despite the decreasing trend in smoking, more than 34 million American adults continue to smoke, more than 16 million live with a smoking-related disease, and about 480,000 die each year from tobacco use.2

A current worrisome trend is the skyrocketing increase in the use of electronic cigarettes, or e-cigarettes. Some people who used to smoke regular cigarettes are now switching to e-cigarettes, thinking they are a safer alternative.3 Another concerning development is the use of e-cigarettes by young people; they are the most commonly used tobacco product among middle and high school students.4,5 E-cigarettes are highly addictive products that produce a wide range of chemicals. A CDC press release from September 6, 2019,6 stated that serious lung illnesses have been associated with e-cigarette products. While it is unclear which chemical components are causing the most damage, users of both THC- and nicotine-containing products have been affected.7

Healthcare providers have a unique opportunity to educate patients about smoking cessation and to offer tools to help them quit. A brief and effective intervention can take less than 10 minutes. An easy way to do this is to use the 5 As:

  • Ask about use
  • Advise to quit
  • Assess willingness to attempt
  • Assist in quitting
  • Arrange for a follow-up

Even for patients who are not ready to commit to stopping smoking, simply discussing a smoking habit with a clinician has been shown to boost motivation and increase the likelihood of future cessation.8

In counseling to enhance motivation, the 5 Rs strategy may be useful:

  • Relevance (make it personally relevant to the patient)
  • Risks (address acute, chronic, and environmental effects)
  • Rewards (such as improved health, appearance, and money saved)
  • Roadblocks (withdrawal, cravings, and resources)
  • Repetition (repeat it every time for unmotivated patients; most people make more than one attempt to quit).

In addition to counseling techniques, several first-line medications have been shown to increase long-term smoking abstinence rates, including bupropion SR, varenicline, and nicotine-containing products (eg, gum). Appropriate counseling on possible side effects and expectations is a must when adding any ancillary medicines. While both counseling and medication can be used individually, the combination of the 2 is more effective.8

Given the current epidemic of tobacco use and its effect on global health, research, such as that described in this article, on how to circumvent the harmful effects of tobacco products is timely. In this study, aloe polysaccharide and propolis extracts, both separately and in combination, limited exposure to carcinogens by enhancing their urinary excretion. Tobacco smoke contains at least 70 human carcinogens. BaP, one of the first such identified carcinogens, was eliminated via urine most effectively in subjects who had received aloe polysaccharide, either alone or in combination with propolis extract.

This study also measured the excretion of cotinine, a major metabolite of nicotine and a marker of choice for monitoring tobacco smoke inhalation. Cotinine excretion was also enhanced by aloe and propolis products. Aloe polysaccharide extract alone was more effective than propolis extract alone, and the combination of the 2 extracts had an effect similar to that of aloe polysaccharides alone. The authors of this study suggest that the enhanced excretion of carcinogens may be chemopreventive by limiting the interaction of electrophilic carcinogens with biomolecules.

Aloe vera has long been used as a folk remedy for the topical treatment of wounds and burns. It has also been suggested to have antimicrobial, antidiabetic, antioxidant, and analgesic effects. It has been applied in patients with skin conditions, arthritis, and gastric ulcers.9 Aloe plants consist of an outer rind, sheath cells of the leaves, called latex, and an inner clear gel. Anthraquinone glycosides (eg, emodin) are derived from latex and have laxative effects. Aloe polysaccharides are the main constituents of the inner leaf gel of aloe and have been shown to have chemopreventive and immune-modulating effects.10 Aloe polysaccharide extract was used in the present study.

Propolis is a natural resinous mixture produced by honeybees from substances collected from parts of plants, buds, and exudates. It is known to have antibacterial, antifungal, antioxidant and anti-inflammatory activities,11 as well as antidiabetic and hepatoprotective activity.12 In this study, a preparation of water-soluble powder was produced by freeze-drying ethanol extract.

In addition to enhancing the excretion of BaP and cotinine, aloe polysaccharide and propolis also lowered blood levels of creatinine, glucose and total bilirubin, which is associated with protective effects on the kidneys and the liver, as well as antidiabetic activity.

Both aloe polysaccharides and propolis have excellent safety records and could be useful as potential chemopreventive agents in patients who are current smokers or who are trying to quit smoking.

Categorized Under


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