Calaguala is a type of tropical and subtropical fern with the scientific name Polypodium leucotomos. It is native to the rainforests of the Americas, while in the jungles of Honduras it lives in symbiosis with palm trees.
The name of the plant comes from the very dense scales that cover the rhizome, which have a particular golden-brown color. It is part of the group of rhizomatous ferns and the rhizome normally has a diameter between 8 and 15 mm, reaching 30 mm in exceptional cases. Fronds have various nuances of green, from glaucous to bright. They are very large in size, starting from 30 cm up to 130 cm long, with a width between 10 and 30 cm and a maximum of 35 pinnae. The fronds have undulate margins and tend to be extremely lobed (or pinnatifid, in botanical terms).
The behaviour of the plant depends on the local climate, it is evergreen in areas with permanent rainfall and only partially evergreen or even deciduous, losing its fronds for a short time during dry seasons. Each side of the pinna midrib is lined with multiple round sori, while the spores are minute and spread using the wind. Like all plants of the Phlebodium genus, the sorus is a cluster of sporangia in order to spawn new ferns, characteristic for this genus.
Rhizomes, fronds, leaves.
Ferns are one of the most ancient plants still surviving today and have been traditionally used in medicine since the earliest days of mankind. Ferns are considered to have a number of similar general properties: they cleanse the blood, provide an energy boost and are useful in the treatment of upper tract respiratory problems, especially as an expectorant. Calaguala is no exception, being effective against these diseases.
In the rainforests of Honduras, the local tribes have used it for a long time in traditional medicine in order to treat a wide array of problems. The classical Mayans even included Polypodium leucotomos in their daily diet as a tea, believing in its ability to clear blood toxins. It is still in widespread use in the country today and the tea is considered to be effective against several types of health issues.
The most frequent use of calaguala is as a tea, for its anti-inflammatory properties and against skin diseases. The skin problems treated with an oral dose of calaguala are very diverse: from eczema and inflammation to depigmentation of the skin (vitiligo), psoriasis, dermatitis or the removal of patches of unusually dark skin (this condition is named melasma). However, drinking calaguala tea can also protect the skin against UV rays and sunburn, as well as PMLE (or the polymorphous light eruption). It is also helpful in the treatment of melanoma (skin cancer) and other forms of cancer as well as the Alzheimer’s disease.
Modern research of calaguala is far from complete but some studies have focused on its effects on degenerative diseases. According to some preliminary results, a daily dose of 360 mg of Polypodium leucotomos extract for 4 weeks can potentially help dementia patients in a moderate stage, partially restoring their mental strength. Strangely, a separate study has failed to observe any positive effects after administering a double dose of 720 mg of extract. These contrasting results are hard to explain and more studies are needed.
Scientists have also investigated claims that calaguala can protect against the harmful action of direct sunlight. According to the partial results of one study, a calaguala extract decreases the damage done to the skin and prevents it from turning red. A separate study has also found that calaguala extracts and lotions protect the skin from UV rays and decrease sun damage.
There are several theories why calaguala is effective against sunburn and UV rays. The most plausible is that the combination of antioxidant and anti-inflammatory effects has a dual action: it shields the skin from most of the damage and allows it to heal faster afterwards. Another possible explanation is the oral administration of the calaguala extract. This allows it to reach the blood stream and work from the inside, healing the tissues in areas where normal products, which are applied on the skin, cannot reach.
This fern is very rich in phenols, which are believed to have a strong antioxidant activity. These are able to neutralize the free radicals produced after exposure to direct sunlight or other forms of ultraviolet radiation, shielding the skin from erythema and stopping any oxidation of the cells. As a result, sunburn risk is decreased and the red skin effect after sun exposure is diminished. The free radicals generated by sun exposure, in particular the very active oxygen molecules, are also to blame for numerous skin issues. Calaguala extract can eliminate them and prevent skin aging, preventing permanent DNA damage.
People who suffer from polymorphous light eruption (also named polymorphic light eruption) can especially benefit from the effects of the fern extract. Such people are extremely vulnerable to sunlight and the plant can offer them a strong level of UV protection. Again, this reduces redness and irritation, which can commonly develop on the skin of sensitive people.
The ability of calaguala to reduce inflammation is squally beneficial for the skin. On one hand, it stops the inhibition of the immune response, the so-called immunosuppression. This effect can cause permanent cellular damage if unchecked. On the other hand, the fern also reduces blood vessel expansion, the most common problem related to inflammation. People with eczema and psoriasis can fully take advantage of the anti-inflammatory effects. The plant will significantly reduce the irritated and burnt skin patches caused by these unpleasant conditions.
Calaguala can also balance the action of cytokines, in particular at skin level. These cells are actually a part of the immune system but if their level becomes too high it can cause not only tissue damage and inflammation, but also the incurable auto-immune diseases. If cytokines work correctly, they can increase the healing rate of skin damage and reduce inflammation.
This effect is very useful for people who suffer from severe skin diseases like vitiligo or psoriasis and are treated using very strong UV radiation. Calaguala extracts can protect their skin and reduce the risk of phototoxicity. Similarly, the skin is better protected during PUVA treatment, which is a combination of psoralen plus ultraviolet A light.
Traditional medical practitioners in the jungles of Brazil believe the fern to have many other qualities. It is not only used to treat skin conditions like dermatitis, but also rheumatism and the whole range of upper respiratory issues like bronchitis, colds, cough and various strains of flu. According to local traditions, calaguala acts like an expectorant and a tonic, as well as increasing sweating and detoxifying the blood. Peruvian herbalists also employ the plant’s rhizome against a variety of diseases: infections, cough, fever and all types of skin problems from boils to abscesses.
Other tribes that inhabit the rainforests of the area use the rhizome and the leaves of the fern as a general medicine. The conditions treated are pretty much the same and include psoriasis, inflammation, diarrhea, arthritis, kidney disorders and even cancer. All across the great basin of the Amazon, this herb is believed to be a great energizer, detoxifier, and booster of the immune system.
The exact mechanism of action is not known but calaguala is able to influence skin color and health. The skin of people who are exposed to strong UV light as part of the treatment for some diseases usually turns dark, but the fern extract is able to reduce this unwelcome side-effect. Strangely, it has the opposite effect on people who suffer from vitiligo. In this case, the extract seems to allow the damaged areas of skin to regain their color, a phenomenon known as re-pigmentation. Scientists suspect that calaguala increases the level of a protein that promotes collagen, thus boosting the collagen production, which would explain the faster skin regeneration.
Side effects and cautions
Calaguala has not been properly researched clinically. It appears not to be toxic when taken orally or externally. However, its long-term effects are not known and it must be treated with caution.
Known possible side effects are skin irritation in some people, as well as stomach disorders when ingested. Like all plants, there is a very small risk of allergies and it should be avoided by people who are allergic to other varieties of fern.