Propolis, the natural 'sting' operation against microbes!

By Jolan Lemmens

Propolis: from bees with love

In the ever-evolving landscape of agriculture, the pursuit of sustainable and innovative alternatives has become paramount, both for the benefit of animal and human health. Traditional farming methods are facing scrutiny due to their environmental impact and potential long-term consequences. As a response to these challenges, there's a rising interest in incorporating nature-based solutions into various sectors, including cattle farming. A particularly intriguing candidate in this context is propolis, a substance ingeniously crafted by bees. With its distinct antimicrobial, antioxidant, and anti-inflammatory properties, propolis presents itself as a potential game-changer in the realm of cattle farming. In this article, we will explore the secrets of propolis, its health benefits and zoom in on its current uses for cattle farming.

In defense of the city

For centuries, natural products have been used as medicinal remedies to address both human and animal illnesses caused by pathogens. In 2015 Tu Youyou received the Nobel Prize for Physiology or Medicine thanks to her discovery of artemisinin, an antimalarial drug derived from Artemis annua. However, Qinghao (Chinese for the Artemis family) has already been among the most frequently recommended herbs in traditional Chinese medicine for more than two millennia [1]. This shows that our newly found interest in natural plant alternatives is backed by thousands of years of traditional usage. The same goes for propolis, which was already used by for example ancient Egyptians to embalm their cadavers and by Incas to reduce fever [2].

The name propolis comes from the Greek words pro and polis, meaning “for/in defense” and “city”. So, here's what propolis really is: it’s the security guard for the hive's entrance, just like a gatekeeper for a city. Propolis is a plant resin made by honeybees (Apis mellifera) to construct and repair their hives and to protect the hive against invaders [2]. For this reason, propolis is also called bee glue. The bees collect “sap” present on and in the plants which they mix with their own salivary enzymes and beeswax [3].

The compounds in propolis

Propolis can be made from poplar in Central Europe, birch in Northern Europe, Acacia in North Africa, and a whole list of other plants worldwide. This is important as the region, plant species, and seasons have an influence on the composition of propolis. As a result of this, more than 300 chemical components of propolis have been identified with its primary components being resins, waxes, polyphenols (including phenolic acids and flavonoids), and terpenoids. Among these, the most pivotal compounds are polyphenols, terpenoids, and aromatic acids. Additionally, propolis contains low amounts of micro and macro elements and vitamins. The diverse array of chemical elements in propolis contributes to its efficacy as an antibacterial agent, as the composition makes it challenging for bacteria to develop resistance [2,3]. The substances are generally recognized as safe substances without toxicity or side effects to humans and animals [4,5].

The unique chemical makeup of propolis sourced from various origins creates the idea that diverse types of propolis will possess different biological characteristics. Still, multiple studies conclusively demonstrate that despite the variations in chemical structure among propolis samples, all samples display noteworthy antibacterial and antifungal properties, with the majority also demonstrating antiviral activity [6].

Figure 1: Composition of propolis

Propolis’ health benefits

Propolis has been known for a long time for (amongst others) its anti-viral, anti-inflammatory, anti-bacterial, anti-fungal, anti-oxidant, and anti-protozoal activity [5].

The majority of studies delving into propolis' potential health benefits have linked it to its phenolic constituents [7]. Propolis acts against microbes (bacteria, viruses, fungi,…) in two different ways. Firstly, it improves the immunity of the human or the animal, so it is better prepared to combat the microbe. Secondly, it acts directly on the microbe itself [5].

Zulhendri and colleagues [7] described three ways in which propolis impacts the well-being of the host:

• Keeping the body's antioxidant system healthy.
• Modulation of pro-inflammatory responses.
• Boosting the body's natural defense system.

Figure 2: the impact of propolis on the pathogens and the host [7]

Anti-bacterial properties

An extensive study investigating propolis’ potential against 600 bacteria concluded that propolis acts against both Gram-positive and Gram-negative bacteria, albeit with varieties depending on the propolis’ geographic location. [2].

So, how does propolis act against bacteria? Amuhayawi [5] summed up 7 methods:

• Reducing the mobility of bacteria by affecting the cell membrane permeability.
• Inhibiting the production of the biofilm by causing damage to the cell membrane.
• Blocking the creation of new nucleic acids, which are the building blocks of genetic material in cells, by flavonoids.
• Reducing bacterial resistance.
• Preventing the formation of proteins.
• Disrupting the normal functioning of the cytoplasmic membrane of the cells, affecting the cells’ overall health and functionality.
• Affecting the bacteria’s energy metabolism.

Interestingly, studies have shown a symbiotic effect of propolis with conventional antibiotics and with other products produced by bees, like honey [8].

Other properties

Propolis has a demonstrated effect on viruses such as herpesvirus, adenovirus, rotavirus, coronavirus, SARS-CoV-2, and influenza viruses and even showed anti-HIV activity. It also has shown antifungal activity against species such as C. albicans, C. parapsilosis, C. tropicalis, C. glabrata, and Aspergillus flavus. Moreover it has a demonstrated effect against various intracellular and extracellular pathogenic protozoa such as Cryptosporidium spp [7].

The flavonoids in propolis are powerful antioxidants that increase the cellular immune response by increasing the production of molecules fighting infections (mRNA for interferon-y) and by activating the proteins that help the cells communicate to coordinate the immune response (cytokines) [2]. Propolis’ antioxidant effect has been thoroughly described with regard to the decrease in free radicals, for example in the healing of burn wounds and premature skin aging [9].

The important anti-inflammatory activity can be explained by the presence of active flavonoids such as quercetin and by the presence of cinnamic acid derivates. Propolis suppresses prostaglandins that cause inflammation, swelling and pain [2]. Propolis has also shown antitumoral, hepaprotective, and antidiabetic activity [2].

The story about the cows and the bees

We all know about the birds and the bees, but what about the cows and the bees? In the last decade research about the influence of propolis on cattle health has been performed, as a result of the search for natural alternatives to antibiotics. Most research has been done on the effects of propolis on mastitis and rumination.

As we already noted, propolis has the ability to inhibit bacterial growth in different ways. Research in Brazil confirmed this as it showed the susceptibility of 13 bacteria causing mastitis in dairy cattle to an ethanolic extract of propolis (e.g. S. aureus, Streptococcus spp., and E. coli) [10]. A study in Egypt proved very potent antibacterial activity against Gram-positive bacteria [11].

The search for greater feed efficiency has increasingly grown. Studies support the idea that propolis improves ruminal fermentation and degradation. In vitro concentrations of acetate, propionate, valerate, and total short-chain fatty acids were enhanced by propolis, improving the ruminal degradation of truly degraded organic matter. In a comparative analysis of propolis and monensin, the researchers noted an increase in ruminal degradability and a reduction in ammonia concentration [12]. Furthermore, methanol extract of Indian propolis improved milk yield, milk composition, and somatic cell count [13].

Source list - From the bees with love: propolis, the natural 'sting' operation against microbes!

[1] Tu, Y. (2016). Artemisinin-A Gift from Traditional Chinese Medicine to the World (Nobel Lecture). Angewandte Chemie, 55(35), 10210–10226.

[2] Wagh, V. D. (2013). Propolis: a wonder bees product and its pharmacological potentials. Advances in Pharmacological Sciences, 2013, 1–11.

[3] Przybyłek, I., & Karpiński, T. M. (2019). Antibacterial properties of propolis. Molecules, 24(11), 2047.

[4] Soltan, Y. A., Morsy, A., Sallam, S. M. A., Hashem, N. M., & Abdalla, A. L. (2016). PROPOLIS as a natural feed additive in ruminant diets; can propolis affect the ruminants performance?: a review. Egyptian Journal of Nutrition and Feeds, 19(1), 73–79.

[5] Almuhayawi, M. S. (2020). Propolis as a novel antibacterial agent. Saudi Journal of Biological Sciences, 27(11), 3079–3086.

[6] Bankova, V. (2005). Recent trends and important developments in propolis research. Evidence-based Complementary and Alternative Medicine, 2(1), 29–32.

[7] Zulhendri, F., Chandrasekaran, K., Kowacz, M., Ravalia, M., Kripal, K., Fearnley, J., & Perera, C. O. (2021). Antiviral, antibacterial, antifungal, and antiparasitic properties of propolis: a review. Foods, 10(6), 1360.

[8] Al-Waili, N. S., Al-Ghamdi, A., Ansari, M. J., Alattal, Y., & Salom, K. (2012). Synergistic Effects of Honey and Propolis toward Drug Multi-Resistant Staphylococcus Aureus, Escherichia Coli and Candida Albicans Isolates in Single and Polymicrobial Cultures. International Journal of Medical Sciences, 9(9), 793–800.

[9] Król, W., Bankova, V., Sforcin, J. M., Szliszka, E., Czuba, Z., & Kuropatnicki, A. K. (2013). Propolis: Properties, application, and its potential. Evidence-based Complementary and Alternative Medicine, 2013, 1–2.

[10] Klhar, G. T., Isola, J. V. V., Da Rosa, C. S., Giehl, D. Z., Martins, A. A., Bartmer, M. E., & Segabinazzi, L. R. (2019). Antimicrobial activity of the ethanolic extract of propolis against bacteria that cause mastitis in cattle. Biotemas, 32(1), 1–10.

[11] Hegazi, A., M. Abdou, A., & Abd Allah, F. (2014). Antimicrobial activity of propolis on the bacterial causes of mastitis. Life Science Journal, 11(5).

[12] Soltan, Y. A., Morsy, A., Sallam, S. M. A., Hashem, N. M., & Abdalla, A. L. (2016b). Propolis as a natural feed additive in ruminant diets; can propolis affect the ruminants performance?: a review. Egyptian Journal of Nutrition and Feeds, 19(1), 73–79.

[13] Alolofi, A. (2019). Impact of propolis on milk yield, composition and somatic cell count of cow breeds at dairy farm of Banaras Hindu University, Varanasi, India. International Journal of Agriculture, Environment and Biotechnology, 12(2).