Aloe vera, a plant recognized for its diverse applications, often reveals a yellow liquid when its leaves are cut. Understanding this yellow liquid is important for anyone utilizing aloe vera at home or considering products derived from the plant. This article clarifies what this liquid is, its biological effects, and how it differs from the clear gel.
Identifying the Yellow Liquid
The yellow liquid that seeps from a cut aloe vera leaf is known as aloe latex, also referred to as sap or exudate. This substance is found in specialized cells located just beneath the outer rind of the leaf, positioned between the rind and the inner clear gel. The primary compound responsible for the latex’s characteristic bitter taste and yellow-brown color is aloin. Aloin is a naturally occurring anthraquinone glycoside. Aloin is a mixture of two diastereomers, aloin A and aloin B. These compounds are part of a larger family of anthraquinones, which contribute to yellow, orange, or red pigments in plants. The concentration of aloin can vary among different aloe species, ranging from 0.1% to 6.6% of the leaf’s dry weight.
Its Biological Properties and Effects
The yellow liquid, primarily due to its aloin content, possesses notable biological properties, particularly when ingested. Aloin is recognized for its strong laxative effect, historically making it a common ingredient in purgatives.
When consumed, aloin undergoes a transformation by intestinal bacteria, which then stimulates the large intestine. This stimulation enhances peristalsis, the muscle contractions that facilitate bowel movements. The laxative action of aloin typically becomes apparent within 6 to 12 hours after ingestion.
While effective for short-term relief of constipation, its potent nature suggests that prolonged use is not recommended. Beyond its internal effects, the yellow liquid can also act as a skin irritant for some individuals upon topical contact.
Distinguishing It from the Clear Gel
It is important to differentiate the yellow aloe latex from the clear, mucilaginous gel found in the inner part of the aloe leaf. The clear gel, which makes up most of the leaf’s interior, is primarily composed of water (around 98.5-99.5%) and various beneficial compounds like polysaccharides, vitamins, minerals, and amino acids. This gel has a thick, jelly-like consistency and is widely used for topical applications, such as soothing burns and moisturizing skin. Its composition gives it properties that support skin health and healing.
In contrast, the yellow latex is a bitter, yellowish-brown fluid located in the vascular bundles directly under the outer skin of the leaf. Its chemical makeup is dominated by aloin, providing its distinct color and laxative properties. Commercial aloe vera products, particularly those intended for oral consumption, undergo processing to remove the aloin, ensuring the product consists mainly of the clear gel’s beneficial components.
Safety Considerations and Proper Handling
Understanding the safety considerations and proper handling of yellow aloe latex is important. Ingesting aloin can lead to a range of undesirable effects, including abdominal cramps, diarrhea, and potential electrolyte imbalances. Prolonged use of aloin-containing products has also raised concerns regarding potential liver issues and, in some cases, kidney damage.
The U.S. Food and Drug Administration (FDA) withdrew aloin-containing laxatives from the market in 2002 due to safety concerns and a lack of data on their long-term effects. For topical application, direct contact with the yellow liquid can cause skin irritation or allergic reactions in sensitive individuals.
When preparing aloe vera leaves at home, it is advisable to minimize exposure to this yellow sap. A common method is to cut the leaf at its base and stand it upright in a container for about 10-20 minutes, allowing the yellow liquid to drain out. This draining process helps to separate the aloin-rich latex from the clear gel, making the gel safer for use. Commercial aloe products, especially those for internal use, are typically processed to ensure aloin levels are very low, often below 10 parts per million (PPM) for oral products.