When the mind drifts to sweet potatoes, it often paints vivid portraits: the enticing caramel-like scents curling through bustling market alleys, the reassuring warmth of a freshly roasted tuber cradled in frost-numbed hands, or the luscious, almost velvety sweetness that dissolves on the tongue. Yet beyond its role as a culinary comfort, this unpretentious root vegetable has quietly emerged as a veritable "goldmine" of health-promoting properties. Recent scientific investigations have cast a spotlight on the sweet potato's leaves, stems, and tubers, revealing an arsenal of bioactive compounds with extraordinary anti-cancer and anti-inflammatory capabilities. This discovery not only elevates the humble sweet potato from a dietary staple to a potential natural health ally but also underscores the profound therapeutic potential hidden within everyday foods.
The Sweet Potato: A Botanical Alchemy of Color and Nutrition
For generations, the scientific community has embarked on a relentless quest to unearth medicinal treasures from the plant kingdom, historically directing their focus toward specialized herbal remedies. However, a paradigm shift is underway, with mounting evidence highlighting the pivotal role of common produce—such as the sweet potato—in preventive health.
The vegetable's striking flesh hues, ranging from snowy white to vibrant orange and deep amethyst purple, serve as more than just visual aesthetics; they are tangible markers of its nutritional complexity. These pigments, primarily anthocyanins and carotenoids, not only dictate the sweet potato's appearance but also underpin its diverse health benefits. While its antioxidant properties have long been celebrated, recent breakthroughs have peeled back the layers to reveal its hitherto unexplored potential in combating inflammatory disorders and neoplastic cell growth.
The Sweet Potato: A Dual Threat to Cancer Cells
Unraveling the Anti-Cancer Arsenal in Leaves and Stems
When we talk about sweet potatoes (also known as yams), the various colors of their tubers - white, yellow, orange, purple, etc. - are the "visual labels" of their nutritional value. These color differences are due to the composition and content of pigments such as anthocyanins and carotenoids, and also imply different health properties: for example, orange-yellow potato flesh is rich in beta-carotene, which helps with antioxidants; while purple potatoes contain high concentrations of anthocyanins and have outstanding anti-inflammatory potential. Although the antioxidant effects of sweet potatoes are widely recognized, their role in the fields of anti-inflammatory and anti-cancer still needs to be further studied.
doi: 10.1186/s12906-025-04770-9
A pioneering study conducted by researchers at Tennessee State University, published in the esteemed journal BMC Complementary Medicine and Therapies, delved into the sweet potato's remarkable ability to inhibit cancer cell proliferation. The study zeroed in on two distinct plant variants: the All Purple cultivar, renowned for its deep purple flesh, from which only the leaves were extracted, and the Carolina Ruby variety, boasting a rich orange hue, from which both leaves and stems were harvested. The research team selected two aggressive cancer cell lines for their analysis: the BT549 breast cancer cell line and the A549 lung cancer cell line, both notorious for their resistance and rapid growth.
Figure: Root and vine characteristics of sweet potato varieties used in this study
To gauge the extracts' efficacy, the scientists employed the Alamar Blue cytotoxicity assay, a sophisticated method that hinges on the metabolic activity of living cells. This assay works on the principle that viable cells possess the enzymatic capacity to reduce the blue, non-fluorescent resazurin to the pink, fluorescent resorufin. The intensity of the fluorescence emitted serves as a direct correlate of cell viability, providing a precise measure of how effectively the extracts suppress cancer cell growth. For benchmarking purposes, the drug tamoxifen, a cornerstone in breast cancer treatment, was used as a positive control, while dimethyl sulfoxide (DMSO) served as a negative control to rule out solvent-related effects.
The results of the study were nothing short of groundbreaking. Both extracts demonstrated a clear dose-dependent inhibition of cancer cell proliferation, a finding that underscored the sweet potato's potential as a targeted anti-cancer agent. The purple-leaf extract from the All Purple cultivar emerged as a particularly potent adversary against breast cancer cells, with an EC₅₀ (half-maximal effective concentration) measured at an astoundingly low 0.002 μg/μl. This indicates that the extract could inhibit 50% of breast cancer cell growth at an incredibly dilute concentration, speaking volumes about its potency.
Figure: Concentration-response curves of sweet potato leaf extracts of different varieties in A549 cells and BT549 cells
Concurrently, the orange-fleshed leaf-stem extract from the Carolina Ruby variety exhibited remarkable efficacy against lung cancer cells, with an EC₅₀ of 0.0014 μg/μl. What truly captivated the research team was the extract's performance at higher concentrations. At 0.0056 μg/μl, the orange extract achieved an impressive 96.07% inhibition of A549 lung cancer cell growth, a figure that surpassed the 95.11% inhibition rate observed with tamoxifen. This marginal yet statistically significant difference hints at the sweet potato extract's potential to outperform conventional chemotherapy agents in specific contexts, opening up exciting possibilities for natural cancer therapeutics.
Figure: Concentration-response curves of sweet potato leaf extracts of different varieties after 24 hours of incubation using the Alamar Blue method
The scientists postulate that the sweet potato's anti-cancer prowess can be attributed to a synergistic blend of bioactive compounds. Chief among these are anthocyanins, the pigments responsible for the purple hue, and an array of polyphenols, including caffeoylquinic acid and quercetin. These compounds act as a multifaceted assault on cancer cells, triggering apoptosis (programmed cell death), disrupting the cell cycle to halt proliferation, and neutralizing free radicals to mitigate oxidative stress, which is known to fuel cancer progression.
Sweet Potato Tubers: Guardians of Gut Health
The Polysaccharide-Powered Defense Against Intestinal Inflammation
While the leaves and stems of the sweet potato have garnered attention for their anti-cancer properties, the tuber itself is no less remarkable, emerging as a key player in gastrointestinal health. A team of Chinese researchers, publishing their findings in RSC Advances, set out to explore the mechanisms by which purple sweet potato polysaccharides (PSPP) modulate gut health, specifically in the context of ulcerative colitis (UC), a debilitating inflammatory bowel disease.
doi: 10.1039/d2ra00310d
UC has seen a troubling rise in incidence across Asia and the Middle East in recent decades, posing a significant public health challenge. Existing pharmacological treatments often come with a litany of side effects, driving scientists to seek safer, natural alternatives. Purple sweet potatoes, rich in complex polysaccharides, have shown promise in preclinical studies for their ability to regulate gut microbiota, boost immune function, and alleviate colonic inflammation. However, the exact mechanisms underpinning these effects remained obscure, prompting the need for deeper investigation.
The study involved the extraction of two distinct PSPP fractions: PSWP-1 and PSAP-1. These extracts were then administered to mice with colitis induced by dextran sulfate sodium (DSS), a chemical known to disrupt the intestinal barrier and trigger inflammatory responses. To unravel the biochemical changes induced by PSPP, the researchers employed ultra-performance liquid chromatography coupled with triple-time-of-flight mass spectrometry (UPLC-Triple-TOF-MS/MS), a state-of-the-art metabolomics technique that allows for the comprehensive analysis of fecal metabolites.
The results revealed a profound impact of PSPP on the murine gut metabolome. The intervention led to significant alterations in 25 metabolites and four key metabolic pathways, including those involved in the biosynthesis of cutin, suberin, and waxes—compounds critical for maintaining the intestinal barrier. Of particular note were the changes in oleic acid and 17-hydroxyprogesterone levels. These compounds, which serve as biomarkers of inflammation, were markedly elevated in the DSS-induced colitis model but were significantly reduced following PSPP treatment, indicating a potent anti-inflammatory effect.
Figure: PCA and PLS-DA scores of mouse fecal metabolic profiles
Digging deeper, the researchers uncovered a complex interplay between PSPP, gut microbiota, and the immune system. The polysaccharides were found to modulate the composition of the gut microbiome, reducing the abundance of pro-inflammatory bacterial species while promoting the growth of beneficial microbes. Concomitantly, PSPP treatment led to a shift in cytokine profiles, suppressing the production of pro-inflammatory markers such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), while increasing the levels of the anti-inflammatory cytokine interleukin-10 (IL-10).
The team further identified nine pro-inflammatory and eight anti-inflammatory microbial metabolites that responded to PSPP intervention, painting a picture of a "microbiota-metabolite-immunity" axis that drives the therapeutic effects of sweet potato polysaccharides. This intricate network of interactions underscores the sweet potato's ability to address colitis through multiple, interconnected mechanisms, offering a more holistic approach to treatment compared to conventional pharmaceuticals.
The Nutritional Landscape of Sweet Potatoes: Beyond the Medicinal
A Deep Dive into Vitamins, Minerals, and Phytochemicals
To truly appreciate the sweet potato's status as a nutritional powerhouse, it is essential to explore its comprehensive biochemical composition. Beyond the bioactive compounds highlighted in the aforementioned studies, sweet potatoes are a veritable cornucopia of essential nutrients.
Chief among these is their remarkable vitamin content. Sweet potatoes are an excellent source of vitamin A, primarily in the form of beta-carotene, the precursor to retinol. A single medium-sized sweet potato can provide over 400% of the recommended daily intake of vitamin A, a nutrient critical for vision, immune function, and skin health. The orange-fleshed varieties, in particular, owe their vibrant color to high beta-carotene levels, making them a natural choice for those looking to boost their vitamin A intake.
In addition to vitamin A, sweet potatoes are rich in vitamin C, a powerful antioxidant that supports collagen synthesis, wound healing, and immune function. They also contain significant amounts of B vitamins, including thiamine, riboflavin, and pyridoxine, which play key roles in energy metabolism and nervous system health.
Mineral-wise, sweet potatoes are a good source of potassium, a mineral essential for maintaining healthy blood pressure and heart function. They also provide manganese, which is involved in bone development and wound healing, and copper, a cofactor for various enzymes involved in energy production and iron metabolism.
Perhaps one of the most underappreciated aspects of sweet potatoes is their dietary fiber content. Both soluble and insoluble fiber are present, with the former helping to regulate blood sugar levels and the latter promoting regular bowel movements. This fiber content, combined with their low glycemic index, makes sweet potatoes an excellent choice for individuals looking to manage their blood sugar or improve digestive health.
The phytochemical profile of sweet potatoes is equally impressive. In addition to anthocyanins and carotenoids, sweet potatoes contain a variety of phenolic compounds, including chlorogenic acid, which has been linked to antioxidant and anti-inflammatory effects. These compounds work in tandem with the vitamins and minerals to provide a broad spectrum of health benefits, from reducing oxidative stress to modulating immune responses.
Conclusion: A Root-to-Leaf Elixir from Nature
From the tips of its leafy greens to the depths of its starchy tubers, the sweet potato stands as a testament to nature's ingenuity and generosity. What was once dismissed as a simple, rustic food has now been revealed as a complex biological pharmacy, packed with polysaccharides, dietary fiber, vitamins, minerals, and an array of phytochemicals. This unassuming vegetable offers more than just sustenance; it provides a comprehensive approach to health, addressing some of the most pressing health challenges of the modern era, from cancer to inflammatory bowel disease.
The beauty of the sweet potato lies not only in its scientific validated health benefits but also in its accessibility. Unlike many exotic superfoods, sweet potatoes are widely available, affordable, and versatile in the kitchen. They can be roasted, mashed, fried, or even incorporated into sweet treats, making it easy to include them in a daily diet.
As research into the sweet potato continues to unfold, it is clear that we have only just begun to scratch the surface of its potential. Each new study peels back another layer, revealing more about how this humble root can support human health. Whether enjoyed as a comforting winter meal or incorporated into a balanced diet for its therapeutic properties, the sweet potato cements its place not just as a food, but as a powerful ally in the pursuit of wellness.
So, the next time you hold a warm sweet potato in your hands, take a moment to appreciate the botanical marvel it represents. With each bite, you're not just enjoying a delicious meal—you're partaking in a natural remedy that has the power to nourish, heal, and protect. In a world increasingly dominated by processed foods and synthetic remedies, the sweet potato serves as a reminder of the profound healing power that lies in nature's pantry.
References
[1] Nwosisi S, Nandwani D, Myles EL. Antiproliferative potential of sweetpotato in breast (BT549) and lung (A549) cancer cell lines. BMC Complement Med Ther. 2025 Feb 26;25(1):79.
[2] Sun J, Liu J, Ren G, et al. Impact of purple sweet potato (Ipomoea batatas L.) polysaccharides on the fecal metabolome in a murine colitis model. RSC Adv. 2022 Apr 12;12(18):11376-11390.