Quelite Agrio : Other Sour Quelites

In my Post Xocoyoli : The Sour Quelite I mention one of my first plant memories involving what we colloquially know as sourgrass. This plant was a variety of Oxalis (Oxalis pes-caprae). This particular plant is indigenous to Southern Africa but has spread around the World. It is considered to be a weed of agricultural crops and the species can be quite difficult to control as several varieties have bulbous roots which are nearly impossible to eradicate.

The name “oxalis” is derived from the Greek “oxus” (oxys) meaning “sharp” or “sour” (1) and, as the name suggests, this plant has a sour taste. The phytochemical responsible for this is oxalic acid whose name was derived from the fact that this acid was first isolated from the leaves of this plant (or one variety of it anyway).

In organic chemistry acids have a sour taste. An acid is a substance that donates hydrogen ions. Because of this, in an acidic solution there are more hydrogen ions (expressed as a pH value) than hydroxide ions. This means the more acidic a food is, the more hydrogen ions are available to trigger the sour taste receptors. Alkaline substances (also called “bases”) have a bitter taste. Ash (which is alkaline in nature) can be used both medicinally (see Post Medicinal Ash.) and culinarily. When used in the kitchen, ash is predominantly used to give a bitter, smoky flavour to food. Diana Kennedy (2010) notes that traditional of cooks in the Valley of Oaxaca will prepare cuanesle, a type of masa, to thicken moles (or to be used for some types of tamales). The preparation of the corn differs from that of masa for tortillas in that the corn is cooked with wood ash instead of lime (see Post Nixtamal). WARNING. Both acid and alkaline substances have the potential to be quite dangerous. Lemon juice (pH 2.0) is considered safe to consume and sulphuric acid (pH 0 – 1) is not and is considered to be quit a destructive poison if swallowed. Edible wood ash (pH 9 – 10.5) is OK to consume in small quantities and lye (pH 13) is as deadly as sulphuric acid if consumed (or spilled on the skin). pH operates on a scale from 0 – 14. pH is reported in “logarithmic units”. Each number represents a 10-fold change in the acidity/basicness. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. pH 7 is considered to be Neutral (for interests sake human blood is pH 7.4)

Interestingly enough the Nahuatl names for sour quelites are usually indicated by a similar prefix (as “oxus” I mean). If you come across xoxo, xoco and sometimes xuco, then you are likely dealing with something sour. Various quelites agrio (agria) (1) in the oxalis family as identified in Nahuatl are as follows.

a Spanish word for sour

Various Nahuatl names for types of sour quelites in the Oxalis family include,

xoxocoiolcuecuepoc (flowering sorrel)=FC=Oxalis sp. (Estrada Lugo 1987 in Pico and Nuez 2000a)
xoxocoiolhuiuila (creeping sorrel)=Oxalis sp.?
xoxocoiol hoihoilan (very bitter)=p. 440 Hernandez Rerum=FC=Oxalis sp. (Estrada Lugo 1987 in Pico and Nuez 2000a)
xoxocoyolhuiuila=FC=Oxalis stricta (Estrada Lugo 1989)
xoxocoyoli=FC=Oxalis sp. or O. violacea (Estrada Lugo 1989)
xoxocoyolcuecuepoc=FC=Biophytum dendroides (Oxalis dendroides) or Oxalis sp. (Estrada Lugo 1989)
xoxocoyoltic/xoxocoioltic =FC540=Oxalis albicans (Estrada Lugo 1987 in Pico and Nuez 2000a; Estrada Lugo 1989) or Oxalis frutescens subsp. angustifolia (O. angustifolia) (Díaz 1976; Estrada Lugo 1989) or O. verticillata (Estrada Lugo 1989)
iztac xoxocoyoli, xoxocoyolhuihuilan, sorrel of various kinds (no species noted)

The word “sorrel” frequently comes up as a name to describe the oxalis. Sorrel as I know it is a European herb of the Rumex species. The two main Varieties are French Sorrel (Rumex scutatus) and Sheep Sorrel (Rumex acetosella). They are both wildcrafted salad/pot herbs utilised for their sour taste.

Now I have mentioned that the one species (O.pes-caprae) originated on the African continent but it is noted in some sources that the species comprises of about 850 species that range from Southern Africa to tropical and the Southern Americas and can be found in Brazil, Bolivia, Argentina, Paraguay, Colombia and into the northern Andes mountains (although some are said to come from southern Asia). (Groom etal 2019)

Medicinal use:

Studies have shown that the roots, stems and leaves of Oxalis pes-caprae have high medicinal utility.

Anti-inflammatory, analgesic, clearing heat, and removing toxicity qualities (1) are attributed to this plant.

these last two clearing heat and removing toxicity are actions noted in Traditional Chinese Medicine. Heat can be found at the qi level, blood level (xue), nutritive level (ying) and within particular organ systems. Proper diagnosis is very important when working to clear heat as improper use of cooling herbs/formulas can weaken the yang and cause any variety of health problems. Formulas used to clear heat are often used for relatively short periods of time with somewhat acute conditions. There is no real equivalent to this in Western medicine (although anti-inflammatory partially covers it). The theory may be more well understood in Curanderismo where the “temperate” nature of foods/medicines/treatment etc. are used for their cooling or heating nature.

In Naila (etal 2018) antibacterial bioassays showed that all samples of the plant tested demonstrated significant antibacterial actions against Xanthomonas, Clavibacter machengnitis and Bacillus at 1000, 1500 and 2500 ppm doses. Dose dependent antifungal activities against the species Aspergillus flavus, Penicillium and Fusarium solani were noticed for all the extracts at 100 and 1000 ppm.

Kabach (etal 2023) have published results on the testing of the evaluation of the antioxidant and antidiabetic properties of Oxalis pes-caprae flowers extract in alloxan-induced diabetic mice.

The flowers and leaves of O. pes-caprae were washed with distilled water, shade dried and powdered to achieve a mean particle size. The plant powder was extracted by maceration with either distilled water or methanol 80% (45 mL/4.5 g of plant powder) at room temperature for 24 h. The water and methanol solvents were then dried in an incubator at 40 °C.

The oral administration of the aqueous and methanolic extracts of the Oxalis pes-caprae flowers (150 mg/kg and 250 mg/kg) daily for 3 weeks resulted in hypoglycaemic effects greater than that of the reference drug, glibenclamide (10 mg/kg).

These results validate the potency of O. pes-caprae as an antidiabetic agent and suggests it could serve as an alternative remedy in ameliorating or protecting against diabetes and its complications.

This is good news as although there are several synthetic hypoglycaemic drugs for the treatment or management of diabetes, such as metformin and sulfonylureas (Cui etal 2022)(Shanmugasundaram etal 2021), these drugs, although potentially useful, can have significant adverse effects that outweigh their therapeutic effects (1)(see Website References)(Gupta etal 2020). In contrast to conventional pharmaceuticals, herbal remedies are widely used for diabetes prevention because of their accessibility, relative safety and wide range of biological activity (Chukwuma etal 2019) (Naveen etal 2021) and as this oxalis has demonstrated efficacy in the management of diabetes it offers options to the vast majority of people in this World who either cannot afford conventional pharmaceutical medications or do not have access to these drugs or the doctors who prescribe them.

Side effects from metformin range from a metallic taste in the mouth to various digestive disturbances such as nausea and loss of appetite to stomach pain, vomiting, diarrhoea and Vitamin B12 deficiencies (which comes with its own set of problems). You are also recommended to call an ambulance if “you get a general feeling of being unwell with severe tiredness, fast or shallow breathing, being cold and a slow heartbeat” or if “the whites of your eyes turn yellow, or your skin turns yellow”. This is usually a sign of hepatitis and acute renal failure is dangerous.

WARNING : This IS NOT a recommendation to replace your diabetic medication with Oxalis extracts. Diabetes can be a life threatening illness if not treated properly.

Acute toxicity study

Compared to safety data, the acute toxicity test at an oral limit dose of 800 mg/kg and 2000 mg/kg of O. pes-caprae flowers methanolic extract caused no changes in mice behaviour and no lethality during the 15 days of observation. Therefore, the extract may be safe at these doses, and the oral LD50 (1) was greater than 2000 mg/kg body weight in mice.

LD50 – the Lethal Dose at which 50% of the test subjects die. LD50 less than 500 mg/kg indicates high toxicity. LD50 500 to 1,000 mg/kg indicates moderate toxicity. LD50 1,000 to 2,000 mg/kg indicates low toxicity

Culinary use:

O.pes-caprae is used in a traditional South African dish called Waterblommetjiebredie (Waterblommetjie bredie) along with another wild flower (that absolutely qualifies as a quelite) called Waterblommetjie (1) after which it gets its name.

Waterblommetjies (‘water flowers’ in Afrikaans) can only be wildcrafted in the wet, winter months (June through September, or sometimes longer, depending on the rainfall) when the blooms carpet the shallow vleie (marshes) that form in the Boland region in the Western Cape.

The dish Waterblommetjie bredie is rich, soupy stew, where the fattiness of lamb is complemented by the delicate, earthy taste of the waterblommetjies and offset by the astringency of wild sorrel and the subtle flavours of a good South African white wine.

The flowers of Aponogeton distachyos

Waterblommetjie bredie (serves 4)

This recipe comes via Jeanne Horak on her Cook Sister Blog (see Website references for a link to her site)

Ingredients:

1kg lamb short ribs, bone in (or 750g lamb leg steaks, cubed)
olive oil
1 large onion, chopped
3 cloves garlic, crushed
250ml dry white wine
500ml lamb or beef stock
salt and pepper
pinch of cayenne pepper
1/2 tsp ground coriander
500g potatoes
400g waterblommetjies (these can also be found canned)
2 handfuls fresh watercress, plus some to garnish **SEE NOTES**

Method:

Pre-heat the oven to 180C.
Heat a little olive oil in a heavy-based pan. Season the meat with salt and pepper and brown in batches in the olive oil. Remove the meat from the pan and transfer to oven-proof casserole. Add the onions, garlic, cayenne pepper and coriander and fry gently until the onions are translucent. Add the onion mix to the casserole (you can deglaze the pan with a splash of the wine, scrape up any bits and add to the casserole dish).
Add the wine, the stock, and the potatoes. Bring to a gentle simmer. Cover the casserole dish with a tight-fitting lid and place in the oven to simmer gently for about 60 minutes (or until the meat is tender.
Add the waterblommetjies on top of the casserole and two good handfuls of watercress. Return to the oven for a further 15 minutes. Before serving, you may want to thicken the gravy either by stirring in a little cornstarch mixed with water, or by mashing up a couple of the potato pieces in the stew and stirring the mash into the gravy.
Serve on creamy mashed potatoes (or with steamed rice , or sweet potato, or corn mush)

**NOTES** the watercress in this recipe replaces the sourgrass used in traditional preparations. In many recipes you will find this herb omitted entirely and lemon juice is used as the souring agent in its stead.

I have also seen reference to the juice (expessed from the stems) of this plant being used to clabber (1) milk in preparation for cheese making

this is the process of thickening and curling milk with a souring agent. Commercial cheese making will use rennet (The traditional source of animal rennet is the stomach lining of calves. The lining contains chysomin, a naturally occurring enzyme, which helps digestion and milk absorption. The enzyme is extracted from the stomach lining of the slaughtered calf, by washing and drying the lining) but home cheese makers might use either vinegar or lemon juice. When I can source a sufficient amount of sourgrass I will publish a recipe Post on making cheese with oxalis juice (Queso de quelite? I’m imagining it to have a green tint to the finished product)

Here’s a quick queso fresco (fresh cheese) recipe. The cheese is similar to a dry ricotta and is ubiquitous in Mexico where it is used to crumble over almost everything. In Mexico queso fresco is often made at home, since the process is fairly simple and does not require aging.

Ingredients

1 gallon (3785ml or just under 3.8 litres) of whole milk (preferably not ultra-pasteurized)
1/2 to 2/3 cup fresh expressed oxalis juice (or use lemon juice or white vinegar nlike a normal person)
Sea salt (to taste)

Method

1. In a heavy-bottomed pot (a pot with a thin base may heat unevenly or too quickly and scald or boil the milk – you don’t really want the milk to boil) and over medium heat, heat milk to 165–185°F (80 – 90C), stirring constantly.

2. Remove from heat. Add lemon juice (or what ever souring agent you’re using) one tablespoon at a time, stirring after each addition. Continue adding lemon juice until the curds separate from the whey.

Your curds should look somewhat like this. The whey is the watery liquid in the pot

3. Let sit at room temperature, uncovered, until cool enough to touch, about 10–20 minutes.

4. Drain curds in a cheesecloth-lined colander or fine mesh strainer set over a large bowl, about 20 minutes. Season with salt to taste.

5. When most of the whey has drained off, lift the edges of the cheesecloth up and twist, wrapping the cheese into a ball, then carefully squeeze off excess whey.

6. Tie off the cheesecloth, return to cheese to a colander, and weigh it down. Press cheese until firm, at least 15 minutes and up to several hours. For a firmer cheese, leave it under the weight longer (overnight is good) in the refrigerator. This will also allow the cheese to dry out a little and make crumbling it easier. For a softer cheese, press it for less time.

O.latifolia has a good record of its culinary use

One of my favourite books on quelites is this one…….

I picked it up from the Museo de la Fundación Herdez in Mexico City (or was it the Museo Nacional de Antropología giftshop? – it was about 10 years ago – I REALLY have to get back to Mexico). Anyhoo, back to the book. This book is an excellent example of how the indigenous people utilise these wild, weedy plants and the following recipe is a perfect example of potentially the only diet available to the poorest campesinos. Tortilla plus herb plus sprinkle of salt and BAM taco de quelite.

The Zapotec people (1) utilise several species of Oxalis. These include…..

• Oxalis alpina Torr.
• Oxalis corniculata L.
• Oxalis corniculata L. ssp. albicans (Kunth) Lourt.
• Oxalis divergens Benth.
• Oxalis hernandezii DC.
• Oxalis cf. latifolia H.B.K.
• Oxalis lunulata Zucc.
• Oxalis magnifica (Rose) Kunth
• Oxalis tetraphylla Cav.
• Oxalis tuberosa Molina

Some Zapotec names for these plants include…

x-có-bè
x-có-bè-làs
guièe-bè
guìzh-bè

In “A Zapotec Natural History” it is noted of the species that it they are a common weedy wild flower of milpas and waste ground and that children eat the small bulbs (“fruits”) of some varieties raw when they are in season (2); they are first washed, then cleaned. The same text also notes that the maguey, Agave potatorum (dòb-bè), is named for the Oxalis, which may be cooked with the maguey piña to add flavour and facilitate fermentation in the mezcal manufacturing process; two varieties are noted : guièe-bè and x-có-bè-làs

The Zapotec are an indigenous people of Mexico. The population is concentrated in the southern state of Oaxaca
at the onset of the rains in June. Many quelites that can only be wildcrafted only become available at this time of year. See Quelites : Quilitl for more information on this.

Other varieties of Oxalis

Oxalis nelsonii.

Rangel-Landa (etal 2016) notes that amongst the Ixcatec speakers of Santa María Ixcatlán (Oaxaca) this plant is known as coyule and is edible. No medicinal use was attributed to it. It is a good example of the bulbous root that can make this plant hard to eradicate. Not all species have roots this big though. It is native to Mexico.

Oxalis dillenii.

Also called : Creeping Oxalis, Yellow Wood Sorrel, Slender wood sorrel. This is a less common variety of oxalis. The seed pods of this variety are somewhat unusual. All oxalis species are edible. The leaves, flowers an, in this case, the green seed pods can be eaten.

Oxalis triangularis is not considered to be a weed species. It can be planted to great effect within the garden and will not invade like other species can. You can find it for sale a specialty nurseries.

Oxalis corniculata.

There is a large amount of information regarding this variety of Oxalis. It is edible (as are they all) and there is a long history of its medicinal use.

Culinary use:

Added to salads, cooked as a potherb with other milder flavoured greens or used to give a sour flavour to other foods. The leaves are available all year round unless the winter is very cold, they have a pleasantly sour taste, but are very small and fiddly to harvest. The leaves contain about 86% water, 2.3% protein, 0.8% fat, 8.2% carbohydrate, 150mg calcium, 78mg phosphorus, 8mg iron, 0.6mg niacin, 78mg vitamin C, 6050µg beta carotene (1). The leaves contain between 7 – 12% oxalate (2).

(Crowe 1990)
(Duke & Ayensu 1985)

Medicinal use:

The whole plant is anthelmintic, antiphlogistic, astringent, depurative, diuretic, emmenagogue, febrifuge, lithontripic (1), stomachic and styptic (2). It is used in the treatment of influenza, fever, urinary tract infections, enteritis, diarrhoea, traumatic injuries, sprains and poisonous snake bites (3). The juice of the plant, mixed with butter, is applied to muscular swellings, boils and pimples (4). An infusion can be used as a wash to rid children of hookworms (5). The plant is a good source of vitamin C and is used as an antiscorbutic in the treatment of scurvy (6). The leaves are used as an antidote to poisoning by the seeds of Datura spp, arsenic and mercury (7). The leaf juice is applied to insect bites, burns and skin eruptions (7). It has an antibacterial activity (7).

Having the quality of, or used for, dissolving or destroying stone in the bladder or kidneys.
(Stuart 1976)(Chopra 1986)
A Barefoot Doctors Manual. Running Press ISBN 0-914294-92-X
(Mandahar 2002)
(Moerman 1998)
(Chopra 1986)
(Duke & Ayensu 1985). This action is known as “refrigerant”. More on this later.

O.corniculata.
An urban weed in Melbourne Australia

O.corniculata is a valuable medicine in Ayurveda (1) where it is known as Changeri. Its Sanskrit names are Ambashta, Amlapatrika, Amlika. It is Amla (sour) and Kashaya (astringent) in Rasa (taste) and Ushna (hot) in Virya (potency). It possesses properties like Deepana (enhancing digestion and metabolism), Grahi (absorptive or binding capacity), Ruchya (taste enhancer), Vata-Kaphahara (pacifies Vata and Kapha) and Pittakara (increases Pitta) (2). The dose for internal use is 5-10ml of Swarasa (fresh juice extract). It can also be used externally. Various studies carried out on this medicinal plant reveals that it possesses anti-inflammatory, anxiolytic, anticonvulsant, antifungal, antiulcer, antinociceptive, anticancer, antidiabetic, hepatoprotective, hypolipidemic, abortifacient, antimicrobial and wound healing properties.

A traditional Hindu system of medicine based on the idea of balance in bodily systems and uses diet, herbal treatment, and yogic breathing to achieve this balance.
Ayurvedic medicine is based on the idea that the world is made up of five elements — aakash (space), jala (water), prithvi (earth), teja (fire), and vayu (air). A combination of each element results in three humors, or doshas, known as vata, kapha, and pitta. These doshas are believed to be responsible for a person’s physiological, mental, and emotional health. Every person is said to have a unique ratio of each dosha, usually with one standing out more than the others. Known for being associated with a tenacious personality, the pitta dosha is based on fire and water. It’s commonly described as hot, light, sharp, oily, liquid, and mobile. Summer is known as pitta season for its sunny, hot days. People with pitta are said to usually have a muscular build, be very athletic, and serve as strong leaders. They’re highly motivated, goal-oriented, and competitive. Still, their aggressive and tenacious nature can be off-putting to some people, which can lead to conflict

Srikanth (etal 2012) have produced a comprehensive review on the phytochemistry and pharmacology of O.corniculata and confirm its traditional uses as having anthelmintic, anti-inflammatory, analgesic, astringent, depurative, diuretic, emmenagogue, febrifuge, relaxant, lithontripic, stomachic and styptic actions. They list the plant as being used for the treatment of influenza, fever, urinary tract infections, enteritis, diarrhoea, traumatic injuries, sprains and poisonous snake bites. In addition to these actions they note the plant as having vulnerary (wound healing), antiamoebic, anti-cancer, anti-diabetic, anti-nociceptive, antioxidant, antifungal, anti-diarrhoeal, antimicrobial, anti-epileptic, anti-ulcer, anti-inflammatory, anxiolytic, hepatoprotective, hypolipidaemic, steroidogenic (1), cardioprotective and hepatoprotective actions.

Steroidogenic enzymes are enzymes that are involved in steroidogenesis and steroid biosynthesis. They are responsible for the biosynthesis of the steroid hormones, including sex steroids and corticosteroids, as well as neurosteroids, from cholesterol

The leaf juice is applied to insect bites, burns and skin eruptions. It has an antibacterial activity. An infusion of leaves is used to remove opacities of the cornea and is dropped into the eyes for itching lids. A decoction of leaves is used as a gargle.

WARNING

Srikanth (etal 2012) notes of O.corniculata that when tested in vivo (in rats) that doses of 100 and 200mg/kg (1) of an extract of this plant has demonstrated significant anti-implantation and abortifacient actions. I would caution against using this herb medicinally or eating large quantities of the fresh plant if you are (or are trying to become) pregnant

the equivalent of 16 to 32 grams in an 80kg adult human

The sourness of these plants are caused by oxalic acid (often just called oxalate or oxalates) and can potentially cause health problems. Pure oxalic acid is a dangerous chemical that can cause headache, dizziness, nausea and vomiting, convulsions, coma and even death. The levels of oxalates in sourgrass do not present the same danger as the pure substance but it is known to increase the risk in those prone to kidney stones and it can be considered an anti-nutrient (1). Oxalic acid can bind to calcium making it unavailable for absorption by the human gut. Excessive consumption of oxalates can lead to the formation of calcium oxalate crystals in renal tubules resulting in acute tubular necrosis (Nelson etal 2020) (Corley etal 2005). Now this little titbit of information is somewhat contradictory. It makes sense that if oxalate binds calcium (rather than allowing the body to absorb it) and then this calcium might then accrete to form stones in renal tubules then it makes less sense that extracts of oxalis herbs can be specific to dissolving these very same kidney stones (the term being lithontripic)(2). I would avoid using this plant medicinally in those prone to kidney stones.

another well known anti-nutrient are the lectins. These can be found in high amounts in uncooked kidney beans. Consuming too many lectins can have adverse effects on health. Some research shows that they could potentially cause adverse symptoms like vomiting and diarrhoea and may also contribute to leaky gut and might cause alterations in immune function (Freed 1999). The good news is that cooking, sprouting, or fermenting foods that are high in lectins can easily reduce their lectin content.
herbs with an established lithontripic action include Crataeva nurvala, Galium verum (Lady’s bedstraw), Allium cepa (onion)

The entire plant is used to treat scurvy and scorbutic conditions.
An infusion of the plant acts as a refrigerant (1) and may be used as a cooling drink in febrile conditions (Burlage, 1968).

refrigerant refers to herbs that have “cooling” properties. This can either be through internal or external use. Herbs such as lemongrass, spearmint, lemon balm and chamomile have cooling properties when taken internally (as a tea). These same herbs have a diaphoretic action (can induce perspiration) which also cools the body as the perspiration evaporates. Other herbs such as chickweed and cleavers have a refrigerant action when applied topically (as a poultice or compress) to the skin.

Scurvy is a disease of nutritional deficiency caused by a lack of vitamin C. Symptoms arise after 6 to 8 weeks and death may occur within 8 to 12 months. Vitamin C deficiency was the cause of more deaths in the 18th Century Naval life than was death in combat and it has been estimated that millions of sailors died as a result of this disease. The voyages of Captain Cook between 1768 and 1799 were the first recorded voyages in which no sailor lost their life to this illness. He is said to have used sauerkraut and a type of orange extract to prevent this, although he is said to have claimed that he did this through the use of a malt extract (which however does not contain vitamin C).

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