IngredientsPasuchaca is the vernacular name for Geranium dielsianum Knuth (synonym Geranium ruizii Hieron.), a perennial plant native to Peru that is traditionally used in South America to treat diabetes, inflammation, and other ailments. The plant belongs to the family Geraniaceae and the large, medicinally significant genus Geranium.
Pasuchaca grows in the wild in the northern Andes at heights of 3,000–3,500 metres above sea level. It is a perennial plant, growing up to 35 cm high. The light-purple flowers grow in bunches. Its stems are brown, hard, and slightly crooked. It mostly grows in the provinces of Cajamarca, Piura, and Ayabaca.
The naming of this plant in the scientific literature has been somewhat variable. It is formally described as Geranium dielsianum Knuth, with the synonym Geranium ruizii Hieron. A separate Peruvian species, Geranium ayavacense, has also been referred to locally under the name "Pasuchaca" and has been the subject of some pharmacological studies. The species Geranium dielsianum Knuth, Geranium lechleri, and Geranium ruizii Hieron. are all known as "pasuchaca" and share common pharmacological activities, including antihypoglycemic, anti-inflammatory, and antidiarrheal activities evaluated in aqueous and ethanolic extracts.
The plant is known primarily as "pasuchaca" in the Andean regions where it grows. A commercial standardized extract has been marketed under the tradename MISKAMISKAâ„¢, under which several formal pharmacological studies have been published.
Scientific investigations have focused on the aerial parts of the plant. Industrial processing studies have demonstrated its potential for producing nutraceutical products, such as wholemeal flour, filter infusion, and a functional additive, with the stem exhibiting particularly high levels of total phenolic content (267.66 mg Gallic Acid Equivalent/g dry mass) and antioxidant activity (12.7 mM Trolox Equivalent/g dry mass).
Processing yields of 70.63 ± 0.50% for flour, 10.82 ± 0.92% for filter infusion, and 6.35 ± 0.96% for functional additive have been reported, with functional evaluation indicating that Pasuchaca has a promising future as a nutraceutical in both the food and pharmaceutical industries.
Pasuchaca (Geranium dielsianum) is a perennial plant found in the Andean highlands of Peru. Over the decades, the decoction of the plant has been consumed as a tea protective against diabetes. It has also traditionally been used as an anti-diabetic, anti-inflammatory, and anti-diarrheal folk medicine.
Local communities commonly consume its decoction as a tea for diabetes prevention. The plant occupies a central role in Andean ethnomedicine, particularly in the northern highland provinces of Peru.
Traditionally, Pasuchaca has been valued for its ability to help regulate blood sugar levels, making it a cornerstone remedy in local folk medicine for managing symptoms associated with diabetes. Healers would often prepare it as a tea or decoction, utilizing its leaves and stems to create infusions believed to support pancreatic health and improve glucose metabolism.
Beyond its role in blood sugar management, Pasuchaca has also been used to address a variety of other ailments. Its astringent properties made it popular for treating gastrointestinal discomfort, diarrhea, and wounds. In traditional remedies, Pasuchaca was sometimes applied topically to promote healing and reduce inflammation.
The astringent use of the plant is consistent with the broader ethnobotanical tradition of the Geranium genus. The Geranium genus is interesting because plants in this genus are rich in phenolics and extracts from geraniums are known to have many health benefits for humans.
Screening, isolation, and identification of the active compounds from Pasuchaca's aerial parts has been performed by coupling a methylglyoxal (MGO)-HPLC screening assay with high-speed counter-current chromatography (HSCCC). Seven dihydroflavonol derivatives were separated and identified from the 80% methanol extract. The compounds identified include 2,3-dihydromyricetin 3-O-α-rhamnopyranoside, (+)-taxifolin 3-O-β-D-xylopyranoside, astilbin, isoastilbin, 3″-acetyl astilbin, and 2″-acetyl astilbin.
Astilbin (dihydroquercetin-3-O-rhamnoside) was identified as the major constituent, with remarkably high contents of 252.41 mg/g in the 80% methanol extract and 541.04 mg/g in the partitioned upper layer fraction.
Astilbin constituted over 25% of the 80% methanol extract and more than 54% of the bioactive partitioned upper layer, firmly establishing it as the key phytochemical marker for Pasuchaca. The astilbin content in the dried aerial parts was determined to be 86.68 mg/g.
This high level is comparable to, and often exceeds, that of other known astilbin-rich plants such as Smilax china L. (1.39–14.10 mg/g), Smilax glabra Roxb. (11.5–47.6 mg/g), and Engelhardia roxburghiana (20.0–86.7 mg/g), underscoring Pasuchaca's potential as a valuable source.
The 2025 study was the first to formally isolate these phytochemicals from Pasuchaca.
Phytochemical analysis of Pasuchaca extracts has confirmed the presence of tannins, flavonoids, alkaloids, terpenes, saponins, and phenolic compounds. These findings are consistent with the broader phytochemical profile of the Geranium genus.
The chemical composition of Geranium species in general includes mainly polyphenolic compounds: ellagitannins, flavonoids, and phenolic acids. Ellagitannins are represented by geraniin, corilagin, pedunculagin, castalagin, and vescalagin. The most frequently isolated flavonoids are aglycones (quercetin, kaempferol, and myricetin) and their glycosides, such as quercitrin, isoquercitrin, hyperoside, astragalin, rutin, and others; proanthocyanidins have also been identified. Gallic, ellagic, ferulic, caffeic, and chlorogenic acids are the main phenolic acids identified in Geranium species.
Given astilbin's diverse pharmacological properties, including anti-inflammatory, hypoglycemic, and antioxidant activities, Pasuchaca warrants further investigation for potential applications in the pharmaceutical and food industries.
The methanolic extract of Pasuchaca was found to suppress blood glucose elevation after oral administration of sucrose, maltose, and starch, but not after oral administration of glucose, in mice. In vitro examination of the inhibitory effect on maltase activity revealed that the extract strongly inhibited mouse small intestine maltase activity. These results suggest that the inhibitory effect on alpha-glucosidase activity might contribute to a delay in carbohydrate digestion and subsequent lowering of blood glucose levels, thereby leading to prevention and management of diabetes.
This mechanism is analogous to that of the pharmaceutical alpha-glucosidase inhibitors (e.g., acarbose), which delay the absorption of dietary carbohydrates. The selectivity for polysaccharides and disaccharides over free glucose (monosaccharide) is consistent with enzyme-level inhibition rather than glucose transport interference.
Advanced glycation end products (AGEs) are a diverse group of compounds formed via non-enzymatic reactions between reducing sugars and proteins, nucleic acids, or lipids, thereby altering their structural and functional integrity.
Astilbin, the major constituent of Pasuchaca, demonstrated potent antiglycation activity across all stages of protein glycation (early, middle, late, and whole stages), significantly surpassing the positive control aminoguanidine. Furthermore, the formation of MGO-astilbin adducts was confirmed by LC-ESI-MS, validating astilbin's role as an effective methylglyoxal (MGO) scavenger.
A previous study had reported that astilbin markedly inhibited the formation of BSA-fructose-mediated AGEs; the 2025 Pasuchaca study further establishes it as a potent antiglycative agent.
Beyond enzyme inhibition, Pasuchaca extracts have demonstrated direct hypoglycemic activity in animal models of diabetes. Under experimental conditions, the aqueous extract of Geranium ayavacense (Pasuchaca) was shown to have hypoglycemic effects in rats.
In male Sprague–Dawley rats, Geranium dielsianum (GD) extract increased levels of Bifidobacteria and Lactobacilli and decreased levels of Clostridium leptum subgroup and Bacteroides group in the intestine. GD extract intake had a prebiotic effect in rats and achieved an increase of Bifidobacteria in the intestine. Furthermore, 3-hydroxyphenylacetic acid was present at high concentrations in the caecal content of the GD extract intake group.
The antioxidant activity of Pasuchaca is attributed to its high polyphenol content. Industrial processing studies have demonstrated that the stem exhibits particularly high levels of total phenolic content (267.66 mg Gallic Acid Equivalent/g dry mass) and antioxidant activity (12.7 mM Trolox Equivalent/g dry mass).
This is the most extensively investigated area for Pasuchaca. However, as of the date of this article, all controlled pharmacological evidence remains at the preclinical (animal) level; no randomized controlled trials in human diabetic populations have been identified in the peer-reviewed literature.
A published study aimed to determine whether the lyophilized aqueous extract of Geranium ayavacense (Pasuchaca) has any effect on glycemia in rats with experimental diabetes mellitus induced with alloxan. Rats with glycemia greater than 200 mg/dL were divided into six groups of eight rats each. Group I received 3 mL of distilled water (control); groups II through VI received Pasuchaca extract at doses of 12.7, 100, 200, 300, and 500 mg/kg, respectively. Basal glycemia was determined, with evaluations performed at the 1st, 3rd, 6th, 12th, and 24th hour after administering the different interventions. Under these experimental conditions, the aqueous extract of Geranium ayavacense was found to have hypoglycemic effects in rats. Limitation: This is an animal model; results cannot be directly extrapolated to humans.
Hyperglycemia was induced with alloxan at doses of 170 mg/kg in male albino mice; animals with blood sugar levels above 250 mg/dL were included. Mice were randomized into five groups: alloxan control, Geranium ruizii extract at 50 mg/kg, 150 mg/kg, and 300 mg/kg per oral, and a glibenclamide positive control (5 mg/kg). At doses of 50, 150, and 300 mg/kg, blood glucose was reduced at 14 days of treatment. The hypoglycemic effect of the hydroalcoholic extract of Geranium ruizii, administered orally in mice with alloxan-induced hyperglycemia, was found to be effective at 150 mg/kg body weight. Limitation: Animal model only; alloxan-induced diabetes does not perfectly replicate human type 2 diabetes pathophysiology.
The methanolic extract of Pasuchaca was found to suppress blood glucose elevation after oral administration of sucrose, maltose, and starch, but not after oral administration of glucose, in mice. In vitro examination of the inhibitory effect on maltase activity revealed strong inhibition of mouse small intestine maltase activity. These results suggest that the inhibitory effect on alpha-glucosidase activity might contribute to a delay in carbohydrate digestion and subsequent lowering of blood glucose levels. Limitation: Animal and in vitro data only; the specific dose used was not detailed in available abstract text.
Summary of evidence strength: The antidiabetic evidence for Pasuchaca is preliminary. It consists of multiple animal studies (rats and mice using alloxan-induced diabetes models) and in vitro enzyme inhibition assays. No published randomized controlled trials in humans have been identified. The consistency of the preclinical findings across different research groups and extract types is notable, but clinical translation remains unestablished.
Pasuchaca was investigated for its antiglycative properties; the study aimed to screen, isolate, and identify the active antiglycative compounds from its aerial parts. By coupling a methylglyoxal (MGO)-HPLC screening assay with high-speed counter-current chromatography (HSCCC), seven dihydroflavonol derivatives were separated and identified from the 80% methanol extract. Astilbin demonstrated potent antiglycation activity across all stages of protein glycation (early, middle, late, and whole stages), significantly surpassing the positive control aminoguanidine. The formation of MGO-astilbin adducts was confirmed by LC-ESI-MS, validating its role as an effective MGO scavenger. This report was the first to isolate these phytochemicals from Pasuchaca. The findings establish astilbin as the key antiglycative component, highlighting its potential as a source of functional food ingredients or natural therapeutics for mitigating glycative stress.
Yonei Y, Takabe W, Yagi M, Takahashi K, Ito M, and Morii H conducted an open-label clinical trial of Geranium dielsianum extract administered for 12 weeks, measuring anti-glycative actions, skin quality, and intestinal environment, published in Glycative Stress Research 3(1): 44–55, 2016. The full results of this trial are not available in free-access repositories and therefore detailed outcomes cannot be reported here beyond the confirmed existence of the trial.
Yonei Y, Ikeda T, Ogawa H, and colleagues published "Anti-glycation and improvement microbiota by Geranium dielsianum extract: Relation to health problems in athletes," in Glycative Stress Research 6(1): 31–38, 2019. This represents an application of the antiglycation and microbiota-modulating properties in a human athletic population. Full outcome data are not available in free-access repositories.
Summary of evidence strength: The antiglycation evidence from laboratory studies (in vitro) is robust and mechanistically well-characterized, with astilbin identified as a potent MGO scavenger. At least two published clinical investigations in humans (2016, 2019) exist for a standardized extract, but their full datasets are not freely accessible, limiting independent assessment of their methodology and outcomes. Evidence remains preliminary to moderate.
Pasuchaca is a perennial plant found in the Andean highlands of Peru whose decoction has been consumed as a tea protective against diabetes; it has also traditionally been used as an anti-diabetic, anti-inflammatory, and anti-diarrheal folk medicine, though there was little scientific evidence elucidating its effects. A study testing GD extract on the intestinal environment in male Sprague–Dawley rats found that GD extract increased levels of Bifidobacteria and Lactobacilli and decreased levels of Clostridium leptum subgroup and Bacteroides group in the intestine; furthermore, 3-hydroxyphenylacetic acid was present at high concentrations in the caecal content of the GD extract intake group. Limitation: Animal study only; microbiota effects in rats may not translate directly to humans.
Summary of evidence strength: Preliminary; single animal study with no human replication found in peer-reviewed literature, though the human clinical trial from 2016 included intestinal environment as an endpoint.
In vitro antioxidant activity for Geranium dielsianum has been reported in studies of Peruvian medicinal plants. Among plants studied from Peru, G. dielsianum presents high values for antioxidant capacity, reaching 1.234 ± 0.031 mmol Trolox/100 ml, which is around three times higher compared to other medicinal species such as L. meyenii and T. ochracea. Scientific investigations have corroborated strong antiglycative activity in vitro, alongside antioxidant properties.
Summary of evidence strength: Preliminary; in vitro data only. No controlled human studies of antioxidant effects have been identified.
Geranium dielsianum Knuth, Geranium lechleri, and Geranium ruizii Hieron., all known as "pasuchaca," share anti-inflammatory and antidiarrheal activity that has been evaluated in aqueous and ethanolic extracts. These effects are consistent with the high tannin content of the plant, as tannins are well-established astringent agents that can reduce intestinal fluid secretion and exert antimicrobial effects.
Summary of evidence strength: Preliminary; based on in vitro and animal studies, with no identified published randomized clinical trials for these specific endpoints.
No standardized clinical dosage for humans has been established through clinical trials as of the evidence available. The following dosages appear only in study protocols as described in peer-reviewed publications:
Traditional preparation involves brewing the dried aerial parts as a decoction; local communities commonly consume its decoction as a tea for diabetes prevention, but no standardized quantity for this traditional preparation has been defined in the peer-reviewed sources identified.
Formal, systematic toxicological assessment of Pasuchaca in humans is lacking in the published peer-reviewed literature identified. The following observations are drawn exclusively from factual content in the sources reviewed:
Given that Pasuchaca extracts have demonstrated alpha-glucosidase inhibitory activity in animal models — a mechanism shared with antidiabetic pharmaceutical agents such as acarbose — the concurrent use of Pasuchaca preparations with antidiabetic medications (including insulin, sulfonylureas, or alpha-glucosidase inhibitors) carries a theoretical risk of additive or synergistic hypoglycemic effects. In animal studies, a glibenclamide comparator was used alongside Pasuchaca extract, indicating researchers acknowledged this pharmacological parallel.
Phytochemical analysis has confirmed the presence of tannins in Pasuchaca extracts. High dietary intake of hydrolyzable tannins can interfere with the absorption of iron and other minerals, and may cause gastrointestinal irritation at high doses, although this has not been specifically tested for Pasuchaca in published studies identified here.
No published clinical safety studies, adverse event reports, or formal toxicological monographs for Pasuchaca have been identified in any of the major regulatory databases searched (NIH ODS, NCCIH, EMA, WHO). The human clinical trials identified (Yonei et al., 2016; Yonei et al., 2019) are published in Glycative Stress Research, a specialized Japanese journal, and their full safety reporting is not available in open-access format.
No current entry for Pasuchaca or Geranium dielsianum has been identified in the WHO monographs on selected medicinal plants, European Pharmacopoeia, ESCOP monographs, or German Commission E records. It is not listed among dietary supplement ingredients reviewed by the NIH Office of Dietary Supplements. It remains a regionally used botanical without formal regulatory monograph status in major international frameworks as of the currently available evidence.
Future research should focus on in vivo studies to confirm the efficacy of astilbin from Pasuchaca and product formulation studies to develop bioavailable astilbin-rich extracts or compounds. Formal safety pharmacology, toxicokinetic studies, and drug interaction profiling in humans represent outstanding gaps in the current evidence base.
The totality of published research on Pasuchaca (Geranium dielsianum) reflects a plant with a coherent and biologically plausible pharmacological profile rooted in its rich dihydroflavonol content — particularly astilbin — and a broad polyphenolic matrix. The most compelling mechanistic work (antiglycation, alpha-glucosidase inhibition) is supported by well-conducted in vitro studies and several animal experiments from independent research groups across Peru and Japan. These findings validate the traditional use of Pasuchaca and position it as a promising, high-yield source of astilbin for the development of functional foods, nutraceuticals, and natural therapeutic agents aimed at mitigating diabetic complications and other age-related diseases. However, the overall evidence in humans is sparse and methodologically limited (open-label design, no available controls, insufficient published detail). Until rigorously controlled clinical trials in relevant human populations are completed and published in full, the antidiabetic, antiglycation, and related health claims for Pasuchaca remain preliminary.
Health conditions that Pasuchaca may help support.
Body systems that Pasuchaca may help support.
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